Inductive Touch Sensor Coil Arrangement for Display Luminance
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Solution Overview
Problem
Conventional touch sensors on display devices often suffer from reduced luminance and inability to accurately detect touch events by fingers due to their placement on the front surface, which can interfere with light emitting regions and fail to sense touch events causing minimal magnetic field changes.
Innovation Solution
A display device with an inductive touch sensor system comprising a coil unit on the front surface, including auxiliary coils that do not overlap with light emitting regions, and a touch sensor on the rear surface, utilizing driving and sensing coils to detect touch events by both stylus and finger, with a controller to process signals from the sensing coils.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the touch sensor is placed on the front surface of the display unit, then the touch sensor can sense touches, but the luminance of the display is reduced due to overlap with light emitting regions
Solution Approach 1:
The touch sensor is moved from the front surface (2D plane overlapping with light emitting regions) to the rear surface of the display unit, changing its spatial dimension. This allows the touch sensor to function without overlapping with the light emitting regions, thereby maintaining display luminance while preserving touch sensing capability.
Solution Approach 2:
Instead of placing the touch sensor on the conventional front surface, the patent inverts the arrangement by placing it on the rear surface of the display unit. This inversion resolves the conflict between touch sensing and light emission by eliminating the spatial overlap that causes luminance reduction.
2Measurement precision
If the touch sensor is placed on the front surface, then touch sensing is enabled, but the sensor fails to detect finger touches effectively due to minimal magnetic field changes
Solution Approach 1:
A coil unit with auxiliary coils is introduced as an intermediary component between the finger touch and the touch sensor. The auxiliary coils generate a magnetic field that is modulated by the finger touch, converting the minimal magnetic field changes into detectable signals that the touch sensor can reliably sense.
Solution Approach 2:
The patent replaces direct mechanical/capacitive touch sensing with an electromagnetic field-based sensing mechanism using auxiliary coils. This substitution enables reliable finger touch detection by utilizing magnetic field modulation instead of relying on minimal direct field changes.
3Measurement precision
If auxiliary coils are added to the coil unit, then touch detection precision is improved, but the device complexity increases
Solution Approach 1:
The coil unit is segmented into multiple auxiliary coils arranged in specific patterns (spiral, circular, or linear). Each auxiliary coil operates independently to detect touch events in different regions, improving overall detection precision while maintaining manageable structural complexity through modular design.
Solution Approach 2:
The auxiliary coils serve multiple functions: they generate magnetic fields for touch detection, modulate fields in response to different touch types (stylus and finger), and enable precise localization of touch events. This multi-functionality justifies the added complexity by delivering enhanced touch detection capabilities.
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 luminance by placing the touch sensor on the rear surface and enables accurate detection of various touch events, including those by fingers, without compromising the aperture ratio or light emission, by using auxiliary coils strategically positioned between light emitting regions.
Implementation Method 1
A touch sensor arranged on a rear surface of the display unit; and a coil unit arranged on a front surface of the display unit, and including a plurality of auxiliary coils
Data Source
AI summary
Provided herein is a display device including a display unit for displaying an image, the display unit including light emitting regions; a touch sensor arranged on a rear surface of the display unit; and a coil unit arranged on a front surface of the display unit, and including a plurality of auxiliary coils.