Electronic Device Touch Sensing Layer Shielding
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Solution Overview
Problem
Existing electronic devices with force touch functionality are bulky due to the thickness of the force sensor and the gap between the sensor and the housing, making them unsuitable for thin and compact designs while also being prone to noise interference.
Innovation Solution
An electronic device with a thin film transistor and organic light emitting device structure, incorporating a shielding layer with a transparent conductive layer and metal pattern, and a touch sensing layer with a pressure response member, which includes piezoelectric or piezoresistive materials, to sense both touch position and force without noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a force sensor is attached to the rear surface of the display panel to sense touch force, then three-dimensional touch information can be generated, but the device becomes thick and bulky due to the sensor thickness and required gap
Solution Approach 1:
The patent combines the touch sensing layer and force sensing layer into a single integrated structure. The touch sensing layer includes a first electrode and second electrode, while the force sensing layer uses the second electrode and third electrode to detect force through capacitance changes. This merging eliminates the need for a separate force sensor attached to the rear surface, thereby reducing device thickness while maintaining both 2D touch position and 3D touch force sensing capabilities.
Solution Approach 2:
The second electrode serves multiple functions: it acts as one of the electrodes for touch position sensing (between first and second electrodes) and simultaneously serves as one of the electrodes for force sensing (between second and third electrodes). This multi-functionality reduces the number of additional components needed, contributing to a thinner device profile while maintaining comprehensive touch sensing capabilities.
2Measurement precision
If a separate force sensor is used to detect touch force, then accurate force measurement is achieved, but the device is prone to noise interference from external electromagnetic sources
Solution Approach 1:
The patent introduces a shielding layer positioned between the display panel and the touch sensing structure. This shielding layer acts as an intermediary that blocks external electromagnetic noise from interfering with the capacitance-based sensing. The shielding layer is connected to ground potential, creating an electromagnetic shield that protects the sensitive touch and force sensing electrodes from external noise sources, thereby improving measurement accuracy without requiring a bulky separate force sensor.
3Adaptability or versatility
If a thick force sensor and gap are used for force sensing, then force detection capability is achieved, but the device complexity increases
Solution Approach 1:
The patent merges the touch sensing and force sensing functions into a single capacitive sensing system. The touch sensing layer with first and second electrodes detects touch position, while the force sensing layer with second and third electrodes detects touch force. Both functions share the same basic structure and sensing mechanism, eliminating the need for complex separate force sensors and reducing overall device complexity while maintaining full functionality.
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
The solution enables the electronic device to maintain a thin profile while accurately sensing touch position and force, reducing noise interference and improving sensitivity and durability.
Implementation Method 1
a pressure response member, which includes piezoelectric or piezoresistive materials, to sense both touch position and force
Implementation Method 2
a pressure response member, which includes piezoelectric or piezoresistive materials, to sense both touch position and force
Implementation Method 3
a shielding layer with a transparent conductive layer and metal pattern, and a touch sensing layer with a pressure response member, which includes piezoelectric or piezoresistive materials, to sense both touch position and force without noise interference
Implementation Method 4
each pixel includes a thin film transistor and an organic light emitting device
Data Source
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Figure 4
AI summary
An electronic device can include: a pixel array layer (320) disposed on a substrate (310) and including a plurality of pixels, each of the plurality of pixels including a thin film transistor and an organic light emitting device; an encapsulation layer covering the pixel array layer (320); a shielding layer (340) disposed on the encapsulation layer; and a touch sensing layer (350) disposed on the shielding layer (340) to sense coordinates of a touch input, in which the touch sensing layer (350) includes a pressure response member (351) for sensing a touch force of the touch input.