Segmented Common Voltage Electrode for Integrated Display Touch Sensor
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Solution Overview
Problem
Conventional capacitive touch screens require separate display and sensor layers, leading to increased thickness, electrical interference, and higher costs due to additional substrates, while also causing undesirable optical effects.
Innovation Solution
Implementing a segmented common voltage electrode that serves both as the Vcom electrode for the display and the drive electrodes for the capacitive sensor, integrating the touch sensor functionality into the display layer, thereby reducing the number of substrates and electrical interference, and improving alignment and optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate display and sensor layers are used, then capacitive sensing functionality is achieved, but thickness increases and optical performance deteriorates
Solution Approach 1:
The patent merges the display and capacitive sensor layers into a single integrated structure. The common voltage electrode of the display serves dual purposes: as the common voltage electrode for liquid crystal control and as the drive electrode for capacitive sensing. This eliminates the need for separate sensor layers, reducing overall thickness while maintaining both display and sensing functionalities.
Solution Approach 2:
The common voltage electrode is designed to perform multiple functions simultaneously. It provides the common voltage potential for liquid crystal pixel operation while also serving as the drive electrode for the capacitive touch sensor. This multi-functionality reduces the number of required components and layers, thereby reducing thickness without compromising sensing capability.
2Reliability
If additional substrate is added for capacitive sensor, then sensing capability is achieved, but manufacturing cost increases
Solution Approach 1:
The patent combines the display and sensor functions within the same substrate structure. By using the existing common voltage electrode of the display as the sensor drive electrode, the patent eliminates the need for an additional substrate layer for the sensor, thereby reducing material costs and simplifying the manufacturing process.
Solution Approach 2:
The common voltage electrode performs dual roles, eliminating the need for separate sensor electrode layers and substrates. This reduces material requirements and manufacturing steps, leading to lower production costs while maintaining full sensing capability.
3Reliability
If separate display and sensor layers are used, then capacitive sensing is achieved, but electrical interference occurs
Solution Approach 1:
By integrating the sensor drive electrode with the display's common voltage electrode, the patent reduces the number of separate electrical layers and interfaces. This minimizes the potential for electrical interference and crosstalk between display and sensor circuits, as they share a common reference potential and physical structure.
4Reliability
If additional substrate is added, then capacitive sensor is implemented, but optical performance deteriorates
Solution Approach 1:
The patent merges the sensor functionality into the existing display substrate, eliminating additional glass or plastic layers that would otherwise impede light transmission. This integration maintains optimal optical properties by removing unnecessary intermediate layers between the light source and the viewer.
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 integration results in a thinner, cost-effective capacitive touch screen with reduced electrical interference and improved optical performance, as well as a higher signal-to-noise ratio for the capacitive sensor.
Implementation Method 1
a first measurement is acquired of a capacitive coupling between the at least one common voltage electrode segment and the at least one receiver sensor electrode
Data Source
AI summary
An integrated display and touch sensor device comprises a plurality of display pixels and a processing system communicatively coupled with a plurality of common voltage electrode segments and with a plurality of receiver sensor electrodes. The plurality of display pixels is configured for displaying information on the display. The processing system is configured for driving a voltage transition onto a common voltage electrode segment of the plurality of common voltage electrode segments. The voltage transition provides a common voltage for refreshing at least one display pixel of the plurality of display pixels, and generates a first electrical signal on at least one receiver sensor electrode of the plurality of receiver sensor electrodes. The processing system is also configured for acquiring a first measurement of a capacitive coupling between the driven common voltage electrode segment and the at least one receiver sensor electrode by measuring the first electrical signal.