Capacitive Touch Screen Idle Mode Power Reduction
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Solution Overview
Problem
Existing touch screen systems face increased power consumption and latency in idle mode due to unnecessary signal processing for touch input detection, which hinders rapid reaction to user inputs and contradicts the trend of miniaturization and slimness in electronic devices.
Innovation Solution
The apparatus and method utilize a capacitive touch screen configuration with alternating phase signals applied to first and second electrodes to detect adjacent objects in both idle and active modes, reducing power consumption and latency by using the same driving structure for both modes without additional circuitry, thus enabling efficient detection of touch coordinates and touch strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If signal processing operations are performed in idle mode to detect touch input coordinates and touch strength, then user input detection capability is maintained, but power consumption increases unnecessarily
Solution Approach 1:
The patent extracts the essential detection function from the full signal processing operation. In idle mode, only the capacitive sensor array is activated to detect object approach, while the coordinate tracking and touch strength calculation algorithms are suspended. This selective activation maintains detection capability while eliminating unnecessary power consumption.
Solution Approach 2:
The patent implements preliminary detection of object approach in idle mode using capacitive sensors before full touch processing is activated. When an object is detected approaching the touch screen, the system transitions to active mode and activates the complete signal processing pipeline, including coordinate tracking and touch strength algorithms, only when needed.
2Use of energy by moving object
If refresh rate is lengthened to reduce power consumption, then power consumption decreases, but latency increases and reaction to touch input deteriorates
Solution Approach 1:
The patent dynamically adjusts the refresh rate based on operational mode. In idle mode, the refresh rate is set to a lower frequency to reduce power consumption. When object approach is detected or the system transitions to active mode, the refresh rate increases to maintain low latency for touch input detection. This dynamic adjustment resolves the contradiction between power consumption and latency.
3Use of energy by moving object
If separate driving structures are configured for active mode and idle mode to reduce power consumption, then power consumption decreases, but device complexity increases and chip area increases
Solution Approach 1:
The patent designs a universal driving structure that serves both idle mode and active mode operations. The same capacitive sensor array, signal source, and detector are used in both modes, with only the control logic and signal processing intensity varying. This multi-functional approach eliminates the need for separate driving circuits, maintaining low device complexity while achieving power consumption reduction through intelligent control.
4Use of energy by moving object
If additional circuits are introduced for separate active and idle mode driving structures, then power consumption control improves, but chip area increases contradicting miniaturization trends
Solution Approach 1:
The patent implements a universal driving structure where the same physical circuits serve dual purposes for idle and active modes. The capacitive sensor array, signal generation circuitry, and detection circuits are shared between both operational states, with power consumption control achieved through software control logic rather than additional hardware. This approach maintains miniaturization by avoiding extra chip area while providing effective power management.
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 approach allows for rapid user input detection in idle mode, reduces power consumption, and maintains miniaturization and slimness standards by eliminating the need for additional components, while ensuring quick reaction times and efficient power usage.
Implementation Method 1
capacitive sensing enables multi-touch sensing and has excellent durability, recognizability, etc.
Implementation Method 2
A capacitive touch screen senses a change in the amount of charge in capacitive sensors on a touch screen panel caused by a user
Implementation Method 3
When a user approaches a sensor, interference occurs in an electric field formed between two electrodes and hinders charge from being accumulated in the sensor
Implementation Method 4
This may be understood as a change of the capacitance resulting from a change in the equivalent permittivity between electrified surfaces caused by approach of the user
Implementation Method 5
When an alternating current (AC) voltage source is connected to the first electrode and an AC waveform is applied to one electrified surface, a change ΔQ in the amount of electrification corresponding to ΔQ=CΔV occurs with respect to C that varies according to the degree of approach of the user, and is converted into a current or voltage by a read-out circuit connected to the second electrode
Data Source
AI summary
Provided are an apparatus and method for detecting an adjacent object, and a method of driving an electronic device. The apparatus includes a substrate, a plurality of first electrodes including a plurality of first electrodes disposed to extend in a first direction on one surface of the substrate, a plurality of second electrodes disposed alternately and in parallel with the first electrodes on the surface of the substrate to form capacitors together with the first electrodes, a signal source configured to generate electrical signals, a detector configured to detect current signals output when the electrical signals are applied to the capacitors, and a controller configured to connect the signal source to the first electrodes and the detector to the second electrodes.