Multi-touch Cover Stackup for Seamless Sensor Integration
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Solution Overview
Problem
Electronic device housings with sensors and display screens face assembly difficulties and aesthetic issues due to the need for light-transmissive apertures, which create discontinuities and a cluttered appearance.
Innovation Solution
A multi-layer cover comprising an outer hardcoat, a structural layer, an IR transmissive ink layer, a mask layer, and a backside hardcoat that allows specific light transmission while maintaining a uniform appearance, reducing warpage, enabling full surface lamination, and hiding sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If openings are formed in the outer cover to provide access for sensors and display screens, then light transmission and sensor access are enabled, but assembly difficulties arise and the surface appears cluttered
Solution Approach 1:
The cover is divided into multiple functional layers: an outer hardcoat layer, a structural layer, an IR transmissive ink layer, a mask layer, and a backside hardcoat layer. Each layer performs a specific function, allowing the system to achieve sensor access and light transmission without creating physical openings in the outer cover, thereby simplifying assembly while maintaining versatility.
Solution Approach 2:
The patent introduces intermediary layers (IR transmissive ink layer, mask layer) that mediate between the outer cover and the sensors/display screens. These intermediary layers enable light transmission and sensor access while maintaining a uniform outer surface appearance, eliminating the need for physical openings and associated assembly complexities.
2Adaptability or versatility
If openings are formed in the outer cover to provide access for sensors and display screens, then light transmission and sensor access are enabled, but the surface appears cluttered and aesthetic appearance deteriorates
Solution Approach 1:
The mask layer is applied selectively in specific regions to control light transmission and sensor access while maintaining a uniform appearance in other areas. This local application of functional layers allows the cover to provide sensor access where needed while preserving aesthetic surface uniformity elsewhere, eliminating the cluttered appearance associated with physical openings.
Solution Approach 2:
The IR transmissive ink layer and mask layer use optical properties (transparency, opacity, color filtering) to control light transmission. The IR transmissive ink allows infrared light passage while the mask layer blocks visible light, creating a uniform visual appearance while enabling sensor access and light transmission functions.
3Shape
If multiple layers are added to enable selective light transmission and hide sensors, then aesthetic appearance improves, but manufacturing complexity increases
Solution Approach 1:
Each layer in the multi-layer cover structure is designed to perform multiple functions: the IR transmissive ink layer provides both light transmission and surface uniformity; the mask layer provides both aesthetic concealment and light blocking; the hardcoat layers provide both protection and structural stability. This multi-functionality reduces the need for additional specialized layers, managing complexity while achieving surface uniformity.
4Strength
If full surface lamination is enabled through backside hardcoat, then bonding strength improves, but warpage and bubble formation increase without proper hardcoat protection
Solution Approach 1:
The backside hardcoat layer is applied beforehand to the structural layer to provide a stable, warpage-resistant surface that prevents bubble formation during lamination. This preparatory hardcoat layer cushions against the potential adverse effects of warpage and bubbling, enabling full surface lamination to achieve maximum bonding strength without compromising structural stability.
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 minimizes warpage, prevents bubble formation, enhances light transmissivity, and provides a seamless, uncluttered visual appearance by allowing selective light passage while maintaining a uniform finish.
Implementation Method 1
an IR transmissive ink layer, a mask layer... allow certain types of light to pass through while blocking others
Implementation Method 2
The backside hardcoat can reduce cover warpage
Implementation Method 3
enable full surface lamination of the cover to the sensor panel
Implementation Method 4
prevent bubbles from forming in transparent windows in the cover
Data Source
AI summary
A multi-layer cover for an electronic device having one or more of a sensor panel, a proximity sensor, an ambient light sensor, and a display device can include an outer hardcoat, a structural layer, an IR transmissive ink layer, a mask layer, and a backside hardcoat. The backside hardcoat can reduce cover warpage, enable full surface lamination of the cover to the sensor panel, prevent bubbles from forming in transparent windows in the cover, enable a wider range of functional inks to be applied in various layering orders to allow certain types of light to pass through while blocking others, and hide the sensors to provide a seamless, uncluttered visual appearance.