Proximity Sensor Capacitance Variation Detection for Display Devices
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Solution Overview
Problem
Display devices with touch panels face challenges in accurately measuring capacitance variations at predetermined distances, limiting their ability to enter call mode effectively, which affects power consumption and call quality.
Innovation Solution
Incorporating a proximity sensor adjacent to the touch panel that detects capacitance variations to determine the shortest distance to an object, with the touch controller providing negative voltage and activating call mode when the object approaches within specific reference distances, allowing the display to stop image display and allocate resources for improved call quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a general touch panel is used to detect proximity, then the device can detect touch input, but it cannot accurately measure capacitance variation at predetermined distances for call mode
Solution Approach 1:
The patent divides the sensing function into two separate components: a touch panel for touch input detection and a dedicated proximity sensor for precise distance measurement. This segmentation allows each component to be optimized for its specific function, enabling accurate capacitance variation measurement at predetermined distances for call mode activation.
Solution Approach 2:
The patent introduces a proximity sensor as an intermediary component between the user and the system. This proximity sensor specifically detects capacitance variations caused by the user's face or hand approaching the device, enabling accurate distance measurement for call mode without interfering with the touch panel's primary function.
2Use of energy by moving object
If the display panel continues to display images during call mode, then visual information is available, but power consumption increases
Solution Approach 1:
The patent implements periodic action by switching the display panel's operation based on detected proximity states. When the proximity sensor detects that the user is within call mode distance, the display panel stops displaying images to reduce power consumption. When the user moves away, the display resumes normal operation, creating a periodic on/off pattern that optimizes energy usage.
3Measurement precision
If the proximity sensor is placed close to the touch panel electrodes, then proximity detection is sensitive, but interference with touch panel operation occurs
Solution Approach 1:
The patent extracts the proximity sensing function from the touch panel structure by placing the proximity sensor in a separate location (such as the bezel area) rather than integrating it directly with the touch panel electrodes. This extraction allows the proximity sensor to detect capacitance variations without interfering with the touch panel's electrode operations, maintaining both sensitivity and reliability.
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
Enhances the accuracy of proximity and call mode functions, reduces power consumption by stopping image display during calls, and optimizes system resources for better call quality.
Implementation Method 1
a proximity sensor which is adjacent to the touch panel and detects proximity with respect to the object based on a capacitance variation
Data Source
AI summary
A display device includes a display panel including pixels, a touch panel including electrodes, a proximity sensor which is adjacent to the touch panel and detects proximity with respect to an object based on a capacitance variation, a display driver which drives the display panel and a touch controller which drives the touch panel and the proximity sensor. Here, the touch controller provides a negative voltage to the proximity sensor when the proximity sensor detects that the object approaches the proximity sensor such that a shortest distance from the object to the proximity sensor is equal to or less than a first reference distance.