Capacitive Display Electrodes for Far-Field Proximity Sensing
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Solution Overview
Problem
Existing proximity sensor devices are unable to accurately perform both touch sensing and proximity sensing due to the shared electrode configuration, which limits their capability to detect input objects beyond a few millimeters above the input surface.
Innovation Solution
The integration of a capacitive sensing device with a display device, featuring a combination of near-field and far-field receiver electrodes with distinct geometric properties, allows for accurate capacitive sensing in both near-field and far-field regions, enabling reliable touch and proximity sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If shared electrode configuration is used for both display updating and touch sensing, then device complexity is reduced, but sensing precision deteriorates for objects more than a few millimeters above the input surface
Solution Approach 1:
The sensing system is segmented into multiple electrode types with specialized functions: transmitter electrodes for generating electric fields, near-field receiver electrodes for detecting objects close to the surface, and far-field receiver electrodes for detecting objects at greater distances. This segmentation allows each electrode type to be optimized for its specific sensing range, resolving the contradiction between device complexity and sensing precision.
Solution Approach 2:
Different regions of the sensing system are assigned different electrode configurations tailored to local sensing requirements. Near-field receiver electrodes are positioned and configured for detecting objects within millimeters of the surface, while far-field receiver electrodes are configured for detecting objects at larger distances. This local optimization enables accurate sensing at multiple distance ranges without requiring a completely separate system for each function.
2Measurement precision
If electrodes are configured for touch sensing, then touch detection capability is improved, but proximity sensing capability deteriorates
Solution Approach 1:
The sensing system achieves multi-functionality by implementing both near-field and far-field receiver electrodes that can detect objects at different distances. The same transmitter electrodes serve both touch sensing and proximity sensing functions, while the dual receiver electrode configurations enable the system to adapt to different sensing requirements, thereby achieving versatility without sacrificing touch sensing accuracy.
Solution Approach 2:
The sensing capability is extended from a single dimension (touch detection at the surface) to multiple dimensions by adding depth sensing capability through far-field receiver electrodes. This dimensional expansion allows the system to detect objects both at the surface level and at various distances above the surface, transforming the sensing system from two-dimensional touch detection to three-dimensional spatial awareness.
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
This solution enables the input device to accurately detect input objects both in contact with and hovering above the surface, enhancing the sensing capabilities beyond the limitations of traditional shared electrode configurations.
Implementation Method 1
capacitive sensing device having a plurality of common electrodes, a plurality of near-field receiver electrodes, and a plurality of far-field receiver electrodes
Data Source
AI summary
Embodiments of the present invention generally provide an input device comprising a display device integrated with a capacitive sensing device. The input device includes a plurality of transmitter electrodes, each transmitter electrode comprising one or more common electrodes configured to be driven for display updating and capacitive sensing, a plurality of near-field receiver electrodes configured to perform capacitive sensing in a near-field sensing region, and a plurality of far-field receiver electrodes configured to perform capacitive sensing in a far-field sensing region. The input device further includes a processing system coupled to the plurality of transmitter electrodes, the plurality of near-field receiver electrodes, and the plurality of far-field receiver electrodes. The processing system is configured to determine a near-field capacitive image based on the first resulting signals received from the near-field receiver electrodes and determine a far-field capacitive image based on the second resulting signals received from the far-field receiver electrodes.