Serrated Electrode Touch Screen for Low-Temperature Signal Stability
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Solution Overview
Problem
Capacitive touch screen panels suffer from low signal-to-noise ratio (SNR), touch failures due to low temperatures, and poor linearity of active pens, particularly in diamond-like sensor patterns.
Innovation Solution
A touch screen panel design featuring a serrated sensing electrode unit, metal grids isolating light sources, and insulating extensions to reduce impedance and improve signal uniformity, combined with serrated notches as floating lands to enhance capacitance and linearity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a diamond-like sensor pattern is used in capacitive touch screen panels, then the manufacturing process is simplified and the structure is compact, but the signal-to-noise ratio becomes low, touch failures occur at low temperatures, and active pen linearity deteriorates
Solution Approach 1:
The sensing electrode unit is divided into multiple serrated segments rather than a continuous diamond shape. Each serrated portion acts as an independent sensing element, increasing the overall signal-to-noise ratio while maintaining the compact diamond-like footprint. This segmentation allows better temperature stability and improved active pen linearity without changing the overall manufacturing approach.
2Area of stationary object
If a diamond-like sensor pattern is used, then the device structure remains compact, but the signal uniformity decreases and active pen linearity becomes poor
Solution Approach 1:
The sensing electrode unit incorporates serrated portions with specific geometric characteristics (each serrated part having dimensions greater than four times the pixel pitch) that locally enhance the electric field distribution. This local quality improvement ensures uniform signal generation across the compact diamond area, thereby improving active pen linearity while maintaining the small form factor.
3Device complexity
If the first metal layer and second metal layer are directly connected, then the electrical connection is simple, but the impedance increases and signal uniformity decreases
Solution Approach 1:
An insulating extension layer is introduced as an intermediary between the first metal layer and second metal layer at the notch region. This insulating extension, formed by the overlay layer extending into the notch, reduces the impedance at the connection point and improves signal uniformity across the touch sensor, while the overall layered structure remains relatively simple.
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 signal quality, reduces touch failures, and improves active pen linearity by increasing SNR and signal uniformity, providing a better user experience.
Implementation Method 1
each sensing electrode unit is serrated... improve a signal quantity and signal uniformity... improve a linearity effect of an active pen
Implementation Method 2
a partial area of the overlay layer extends into and fills a portion of the first notch... to form an insulating extension layer... reduce impedance
Implementation Method 3
the metal wires are distributed among the plurality of light sources to form metal grids, to isolate each light source from remaining light sources
Data Source
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AI summary
Embodiments of this application provide a touch screen panel and an electronic device. A touch integrated circuit layer in the touch screen panel includes a first insulating layer, a first metal layer, a second insulating layer, a second metal layer, and an overlay layer that are stacked. The first metal layer is located between the first insulating layer and the second insulating layer, the second metal layer is located between the second insulating layer and the overlay layer, and the first insulating layer is located between the substrate layer and the first metal layer. The first metal layer and the second metal layer jointly form a touch functional layer, and the touch functional layer at least includes at least one driving electrode unit and a plurality of sensing electrode units. The at least one driving electrode unit is electrically insulated from the plurality of sensing electrode units, and each sensing electrode unit is serrated. In this way, a touch failure problem caused by a low temperature can be improved, a signal quantity and signal uniformity can be improved, and a linearity effect of an active pen can be improved, thereby improving use feeling of a user to a specific extent.