Strengthened Glass Substrate Extraction via Ion-Exchange Segmentation
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Solution Overview
Problem
Strengthened glass substrates are susceptible to edge damage after separation from a glass sheet, particularly due to exposed central tension layers, and electrically conductive coatings are not durable enough to withstand ion-exchange processes, complicating their use in complex-shaped devices like touch screens.
Innovation Solution
Forming channel segments in the glass sheet with remnant webs, ion-exchanging to create compressive stress, applying coatings, and then separating the substrates along these webs or parting lines, followed by finishing the perimeter to ensure it remains under compression, which enhances durability and prevents edge damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the glass substrate is separated from the glass sheet after ion-exchange processing, then the glass substrate can be used as a discrete component, but the central tension layer becomes exposed at the edges making the edge susceptible to damage
Solution Approach 1:
The patent applies preliminary action by performing ion-exchange strengthening on the glass substrate before separation from the glass sheet. This ensures the compressive stress layer is already formed and protected during the separation process, preventing edge damage that would occur if separation were performed first. The strengthening process creates a protective compressive stress field that remains intact through subsequent machining and separation operations.
Solution Approach 2:
The patent applies segmentation by separating the glass substrate from the glass sheet along predetermined break lines after strengthening. This allows the strengthened substrate to be extracted as a discrete component while maintaining the integrity of the compressive stress layer. The segmentation is performed in a controlled manner that preserves the edge protection established during ion-exchange.
2Adaptability or versatility
If electrically conductive coatings are applied to the glass substrate before ion-exchange processing, then the coating can be applied to the entire surface, but the coating cannot withstand the ion-exchange process and deteriorates
Solution Approach 1:
The patent applies preliminary action by performing ion-exchange strengthening on the glass substrate before applying electrically conductive coatings. This sequence ensures the compressive stress layer is already formed and stable, providing a protected substrate that can withstand the coating application process. The coating is applied to the strengthened surface rather than attempting to withstand the ion-exchange process itself.
Solution Approach 2:
The patent extracts the ion-exchange process from the coating application sequence, performing strengthening as a separate preliminary step before coating. This separation allows the coating to be applied to an already-strengthened substrate, eliminating the conflict between coating durability and ion-exchange process conditions.
3Productivity
If the glass substrate is separated after ion-exchange processing, then discrete substrates can be obtained, but additional machining operations are required to finish the perimeter and maintain compression
Solution Approach 1:
The patent applies preliminary action by performing ion-exchange strengthening on the glass substrate before separation and machining operations. This ensures the compressive stress layer is already formed and extends to the edges, providing inherent edge protection that reduces or eliminates the need for additional perimeter finishing operations to maintain compression.
Solution Approach 2:
The patent applies local quality by ensuring the compressive stress layer extends to the edges of the substrate through controlled ion-exchange processing parameters. This localized stress distribution at the edges provides inherent protection against damage, eliminating the need for additional perimeter machining or finishing operations that would be required if the compressive layer did not extend to the edges.
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 method effectively reduces cracking and chipping, enhances the glass substrate's damage tolerance, and allows for the application of durable electrically conductive coatings, ensuring the glass substrates' integrity and functionality in complex geometries.
Implementation Method 1
The ion-exchange process creates a compressive stress at the surfaces of the glass substrate. These compressive stresses extend beneath the surface of the glass substrate to a certain depth, referred to as the depth of layer.
Data Source
AI summary
Methods for extracting strengthened glass substrates from glass sheets are described herein. In one embodiment, the method for extracting strengthened glass substrates from glass sheets comprises forming a plurality of channel segments in the glass sheet. The plurality of channel segments may extend through the thickness of the glass sheet and are separated by remnant glass webs connecting the glass substrate to the glass sheet. The plurality of channel segments extend around a perimeter of the glass substrate. Thereafter, the glass sheet is strengthened by ion-exchange. The glass substrate is then separated from the glass sheet by severing the glass substrate from the remnant glass webs.