Capacitive Touch Screen Using RC Delay for Array Reduction
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Solution Overview
Problem
Capacitive touch screens with array schemes require a large number of arrays and complex structures, leading to increased complexity and cost due to the need for numerous lines and sophisticated Integrated Circuits for touch recognition.
Innovation Solution
A capacitive touch screen design featuring a touch panel with intersecting sub-panels and resistors connected between electrode lines, where a controller outputs scan signals and measures delay times between scan and sensing signals to determine touch positions, reducing the number of arrays and simplifying the structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If array schemes with multiple X and Y lines are used to cover large touch panel areas, then the touch screen can sense touches across the entire panel, but the number of arrays and controlling structures increases, leading to system complexity
Solution Approach 1:
The patent merges the X and Y axis sensing functions into a single linear array of sensing elements. Instead of requiring separate X-array and Y-array structures that intersect across the panel, the invention uses one continuous array that can detect touches along the entire panel area by combining positional information from single-element signals, thereby covering large areas while maintaining simple structure
Solution Approach 2:
The single linear array serves multiple functions: it detects touches along the entire length of the panel, determines touch position through signal timing or amplitude analysis, and eliminates the need for separate scanning control structures. This multi-functional design replaces the traditional multi-array system, reducing structural complexity while maintaining full-area sensing capability
2Reliability
If a large number of scan lines and sensing lines are used to cover the touch panel, then complete touch detection is achieved, but the controller requires more lines and sophisticated Integrated Circuits, increasing cost and complexity
Solution Approach 1:
The patent extracts the essential touch detection function from the complex multi-line scanning system and implements it using a single linear array with simplified signal processing. By removing the need for multiple intersecting scan and sensing lines, the controller structure is dramatically simplified while maintaining complete touch detection capability through the single array's positional sensing
3Measurement precision
If traditional capacitive touch screen arrays are used, then touch positions can be detected, but the number of arrays increases with panel size, requiring more lines and complicated IC structures
Solution Approach 1:
The patent replaces the mechanical array structure (multiple physical sensing lines arranged in grids) with an electrical signal processing approach. Instead of requiring multiple physical arrays to determine position, the invention uses a single linear array where touch position is determined by analyzing the temporal or amplitude characteristics of the electrical signals generated, thereby maintaining measurement precision while eliminating complex physical array structures
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 design significantly reduces the number of arrays, simplifies the controller's role, and lowers costs by using fewer lines and a more straightforward Printed Circuit Board configuration, while maintaining effective touch recognition capabilities.
Implementation Method 1
a first sub panel and a second sub panel intersecting each other, the first sub panel including a first electrode line and a second electrode line in an X axis, a plurality of resistors being connected between the first electrode line and the second electrode line in the X axis
Implementation Method 2
capacitive touch screen senses a variation in capacitance, caused by a user's contact
Implementation Method 3
The capacitive touch screen is coated with materials capable of storing an electric charge and detects a change in capacitance, caused by a user's contact, to determine the presence of a touch
Data Source
AI summary
A touch recognition apparatus and method in a capacitive touch screen are provided. The touch recognition apparatus includes a touch panel and a controller. The touch panel includes a first sub panel and a second panel intersecting each other. The first sub panel includes a first electrode line and a second electrode line in X axis, and a plurality of resistors connected between the first electrode line and the second electrode line in X axis. The controller outputs scan signals to the first electrode line in X axis and the first electrode line in Y axis, receives scan sensing signals through the second electrode line in X axis and the second electrode line in Y axis, and measures delay times between the scan signals and the scan sensing signals to touched positions in X axis and Y axis, respectively.