LED Mounting on Touch Sensor Layer for Thinner Display Stack
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Solution Overview
Problem
The challenge is to further reduce the thickness and weight of portable electronic devices while maintaining their functionality and user experience, as existing display stacks are limited by the number of layers, particularly due to the use of flexible printed circuits (FPCs) for LED light sources, which add complexity and thickness.
Innovation Solution
The solution involves mounting LEDs directly to the touch sensor layer or the cover glass instead of dedicated FPCs, eliminating unnecessary layers and using optically clear adhesive (OCA) materials to bond components, and applying conductive traces directly to the glass for power and control signals, simplifying assembly and reducing the number of FPCs needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If dedicated flexible printed circuits (FPCs) are used for LED light sources, then electrical connection and control are achieved, but device thickness and weight increase
Solution Approach 1:
The patent merges the FPC layer with the touch sensor layer by integrating LED mounting capabilities directly into the touch sensor structure. Conductive traces are deposited directly on the touch sensor layer to provide electrical connections to LEDs, eliminating the need for a separate dedicated FPC layer for lighting. This consolidation reduces the overall number of layers and thickness of the display stack while maintaining both touch sensing and LED electrical connection functions.
Solution Approach 2:
The touch sensor layer is designed to serve multiple functions: it acts as both the touch sensing element and the electrical connection substrate for LED light sources. By making the touch sensor layer universal for both touch input and lighting control, the patent eliminates redundant layers and reduces overall device complexity and thickness.
2Ease of manufacture
If multiple separate layers are used for touch sensor and LED connections, then functional separation is maintained, but manufacturing complexity increases
Solution Approach 1:
The patent combines the touch sensor layer and LED connection layer into a single integrated structure. Conductive traces are deposited directly on the touch sensor layer to provide electrical pathways to the LEDs, eliminating the need for separate FPCs for touch and lighting functions. This integration simplifies the manufacturing process by reducing the number of components that need to be assembled and aligned.
3Strength
If LEDs are mounted on dedicated FPCs, then electrical connection is reliable, but structural integrity is reduced
Solution Approach 1:
The patent integrates LED mounting directly into the rigid touch sensor layer structure, eliminating the need for separate flexible FPC substrates. This integration provides more stable mechanical support and improved structural integrity while maintaining reliable electrical connections through directly deposited conductive traces on the touch sensor layer.
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 configuration reduces the overall thickness of the display stack, simplifies the manufacturing process, and enhances the structural integrity and durability of the device, while providing a more natural viewing experience with even illumination, thus addressing the need for thinner and lighter electronic devices.
Implementation Method 1
using optically clear adhesive (OCA) materials to bond components
Implementation Method 2
front light subsystems that provide light to illuminate the display screen
Implementation Method 3
a lightguide as a replacement for one of the glass layers
Data Source
AI summary
Electronic devices having a display stack that includes LED light sources combined with at least one other component layer are described. In some instances, the LED light sources are coupled to a dedicated touch sensor circuit layer, which removes an entire layer from the display stack. The touch sensor circuit layer can be installed with an addition portion of flexible printed circuitry extending the length of a lightguide and the LEDs can be installed on that flex. In other instances, particularly when the touch sensor layer is deposited directly on the interior surface of the cover glass, the LEDs can also be mounted to the glass itself, thereby potentially eliminating two layers from the display stack. While the elimination of any layers within the display stack enable the display stack to have a reduced thickness, there also are significant improves as a result of the elimination of the layers because there is a similar elimination of one or more flex printed circuits that must dealt with during the final assembly process of the electronic device itself.