CDA Area Reconfiguration for Faster Capacitive Object Sensing
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Solution Overview
Problem
Existing capacitive sensing devices face issues with high time consumption and current consumption due to the formation of sensor patterns that act as both Tx and Rx, leading to increased time constants and delays in signal transmission, especially when used on display devices like OLEDs.
Innovation Solution
A capacitive sensing device is designed with a small number of capacitance sensing areas organized as independent islands, utilizing a dedicated power line for Tx signal transmission and reducing the time constant by employing a boost voltage to improve the speed of signal rise and fall times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If sensor patterns are formed as independent islands acting as both Tx and Rx, then sensing coverage is improved, but the number of signal lines increases to 20, causing time consumption and high current consumption
Solution Approach 1:
The sensor patterns are divided into separate functional groups: dedicated Tx sensor patterns for signal transmission and dedicated Rx sensor patterns for signal reception. This segmentation allows each group to be optimized for its specific function, reducing the time required for each operation while maintaining comprehensive sensing coverage through the combined functionality of both groups.
2Adaptability or versatility
If sensor patterns are formed as independent islands acting as both Tx and Rx, then sensing coverage is improved, but current consumption increases
Solution Approach 1:
The sensor patterns are divided into separate functional groups: dedicated Tx sensor patterns for signal transmission and dedicated Rx sensor patterns for signal reception. This segmentation allows each group to be optimized for its specific function, reducing the time required for each operation while maintaining comprehensive sensing coverage through the combined functionality of both groups.
3Ease of manufacture
If Tx signal is transmitted through insulator on OLED cathode, then display structure is maintained, but common electrode capacitance becomes excessively large, increasing RC time constant and delaying signal transmission
Solution Approach 1:
A dedicated Tx signal line is introduced as an intermediary component to transmit the Tx signal directly from the Tx sensor pattern to the Rx sensor pattern. This dedicated pathway bypasses the high-capacitance route through the OLED common electrode, significantly reducing the RC time constant and accelerating signal transmission while preserving the display's structural integrity.
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 configuration reduces transmission time and current consumption by quickly identifying the presence of objects like pens or fingers, enhancing the efficiency of signal processing.
Implementation Method 1
Capacitive input devices detect changes in capacitance or voltage that occur when a finger or pen is placed adjacent to or in contact with a 'capacitance sensing area' placed on the top surface of the display
Implementation Method 2
by transmitting Tx using a dedicated power line instead of the Tx transmit signal line provided by the semiconductor IC, the time constant composed of RC is reduced and the speed of the rise and fall time of Tx is improved
Data Source
AI summary
The present invention presents a method for quickly transmitting and receiving pen Tx and Rx signals by reconfiguring a CDA column consisting of a large number of CDAs into a CDA column consisting of one CDA, and reducing the time of the process by detecting objects by quick search with the same CDA column, thereby preventing loss of signals that may occur in Tx/Rx with the pen and reducing current consumption.