Driven Shield for Capacitance Sensor in Mobile Ear-Speaker Mode
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Solution Overview
Problem
The integration of proximity sensors with edge-to-edge OLED displays in mobile devices leads to attenuation and complexity issues, including visible watermarks due to light interaction with inner layers, and challenges in distinguishing between front and back object proximity for capacitive sensing.
Innovation Solution
A method and system utilizing a driven shield to selectively shield a dual-purpose antenna from sensing capacitance on specific sides of a mobile device during active phone calls, allowing it to function as both an antenna and a single-sided capacitance sensor, preventing accidental touch screen disabling by the user's body from the back side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a proximity sensor is placed under the OLED display, then the display size can be maximized for edge-to-edge design, but this causes attenuation, visible watermarks, and added complexity
Solution Approach 1:
The patent makes the antenna serve dual purposes: it functions as both an RF antenna for wireless communication and as a capacitive proximity sensor. By integrating these two functions into a single component, the design eliminates the need for separate proximity sensor hardware under the display, thereby reducing complexity while maintaining edge-to-edge display capabilities
Solution Approach 2:
The patent combines the antenna and proximity sensor functions into a single integrated structure. The antenna elements are designed to simultaneously detect RF signals and capacitance changes from nearby objects, merging two previously separate components into one unified element that reduces overall device complexity
2Device complexity
If a dual-purpose antenna is used for both RF communication and capacitance sensing, then device complexity is reduced, but the antenna cannot distinguish between front and back side proximity during ear speaker mode
Solution Approach 1:
The patent divides the antenna into multiple segments or elements that can be independently controlled. During ear speaker mode, specific antenna segments are selectively activated or deactivated based on the desired sensing direction, allowing the system to distinguish between front and back side proximity by controlling which segments are active
Solution Approach 2:
The patent implements dynamic control of the antenna segments where the active sensing elements are adjusted in real-time based on the operational mode. During ear speaker mode, the system dynamically activates only the antenna segments facing the user's ear, enabling precise directional proximity detection while maintaining the dual-purpose functionality
3Adaptability or versatility
If the capacitance sensor detects objects on all sides, then comprehensive proximity detection is achieved, but accidental touch screen disabling occurs when the user's body is near the back side
Solution Approach 1:
The patent applies different sensing characteristics to different parts of the antenna structure. Specific antenna segments are optimized for detecting objects in particular directions, with enhanced sensitivity toward the front side where the display is located and reduced sensitivity toward the back side, thereby preventing false activations from the user's body while maintaining comprehensive front coverage
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
Effectively addresses the attenuation and complexity issues by enabling precise proximity detection, reducing watermarks, and preventing accidental touch screen activation from the back side during phone calls, while maintaining antenna functionality.
Implementation Method 1
activating a driven shield to at least partially shield the capacitance sensor from sensing object capacitance
Implementation Method 2
capacitance sensor from sensing object capacitance
Data Source
AI summary
A method, a mobile device, and a computer program product enable capacitive proximity sensing in a mobile device. The method includes determining, by a controller of a mobile device, whether the mobile device is participating in an active phone call. In response to determining that the mobile device is participating in an active phone call, the method further includes determining if an ear speaker mode of the mobile device is enabled. In response to determining that the ear speaker mode of the mobile device is enabled, the method further includes activating a driven shield to at least partially shield a capacitance sensor from sensing object capacitance at a second side of the mobile device that is opposed to a first side with the ear speaker.