Touchscreen Proximity Sensing for Low-Power Wake Detection
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Solution Overview
Problem
Capacitive touchscreen devices face challenges in managing power consumption and responsiveness, particularly in standby modes, due to their limited battery life and inability to detect user interactions at a distance effectively.
Innovation Solution
Implementing a low-power, longer-range object sensor that detects user presence or absence at a distance from the touchscreen, allowing the touchscreen to transition between low-power and high-power modes based on user proximity, thereby optimizing energy consumption and responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the touchscreen sensor operates continuously at high scan rate to ensure responsiveness, then user interaction detection is improved, but power consumption increases
Solution Approach 1:
The patent implements dynamic adjustment of the touchscreen sensor's scan rate based on user proximity detection. When a user is detected by the first sensor, the second sensor increases its scan rate to enhance responsiveness. When no user is present, the scan rate decreases to conserve power. This dynamic adaptation resolves the contradiction between maintaining high responsiveness and reducing power consumption.
Solution Approach 2:
The system performs preliminary detection of user presence using the first sensor before activating the second touchscreen sensor at high scan rate. This preliminary action allows the system to prepare for potential user interaction without continuously operating at full power, thereby reducing overall power consumption while maintaining responsiveness when needed.
2Use of energy by moving object
If the touchscreen sensor operates at low scan rate to conserve power, then power consumption is reduced, but responsiveness to user interaction deteriorates
Solution Approach 1:
The system dynamically adjusts the scan rate of the touchscreen sensor based on real-time user proximity detection. When the first sensor detects a user within the first detection zone, the second sensor's scan rate is increased to ensure responsive interaction. This dynamic adjustment allows the system to maintain low power consumption during idle periods while achieving high responsiveness when users are present.
3Measurement precision
If the touchscreen uses short-range capacitance sensing to detect user contact, then detection precision at contact point is improved, but detection range is limited
Solution Approach 1:
The patent divides the detection function into two segments: the first sensor handles long-range user presence detection, while the second capacitive touchscreen sensor handles precise contact point detection. This segmentation allows the system to achieve both extended detection range and high measurement precision by using different sensors for different detection tasks.
Solution Approach 2:
The first sensor acts as an intermediary that detects user presence at a distance and triggers the activation of the second touchscreen sensor. This intermediary detection mechanism extends the overall detection range of the system without compromising the precision of the primary touchscreen sensor when it is activated.
4Speed
If the touchscreen remains in high-power mode to ensure immediate responsiveness, then responsiveness is improved, but battery life is reduced
Solution Approach 1:
The system performs preliminary detection of user presence using the low-power first sensor before activating the high-power second touchscreen sensor. This preliminary action allows the system to remain in low-power mode during extended idle periods while still being able to quickly respond to user interactions when they occur, thereby extending battery life without sacrificing responsiveness.
Solution Approach 2:
The system dynamically transitions between low-power and high-power modes based on user proximity detection. When no user is present, the system operates in low-power mode with reduced scan rate. When a user is detected, the system switches to high-power mode to ensure immediate responsiveness. This dynamic mode switching resolves the contradiction between responsiveness and battery life.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution reduces power consumption and enhances responsiveness by enabling the touchscreen to anticipate user interactions, minimizing time in high-consumption modes and conserving battery life.
Implementation Method 1
Touchscreen displays are commonly implemented with capacitance sensing capability, wherein arrays of electrodes at or below a cover glass material are used to sense a change in capacitance caused by introduction of a user instrument
Implementation Method 2
arrays of electrodes at or below a cover glass material are used to sense a change in capacitance caused by introduction of a user instrument
Data Source
AI summary
Sensors capable of detection of user objects within different detection zones can be used to reduce power consumption of a touch screen interface of an electronic device, even while the device is in a suspended or sleep state. At least one object sensor, such as a capacitive sensor, has a detection zone or range exceeding the range of a touch screen sensor, so the touch screen sensor can be placed into a low power state until the object sensor detects a user object in a position approaching the touch screen. The object sensor(s) are positioned around or within the perimeter of the interaction area of the touch screen. The object sensor(s) can have less power consumption than the touch screen sensors, so the electronic device can have extended standby battery life or other more energy efficient operation. Object sensors are also used to detect gestures or user object positioning.