Gorilla Glass Research Articles

Strength Increase of Alumina Foams by a Sodium Aluminosilicate Glass Coating with Subsequent Na+ ↔ K+ Ion Exchange (Gorilla Glass Coating)

Reticulated alumina ceramic foams manufactured by the Schwartzwalder technique are coated with a sodium aluminosilicate glass using an aqueous precursor containing alumina particles and sodium silicate. After a heat treatment, a well‐adhering glass layer with a thickness between 10 and 120 μm is obtained. Besides the strut surface, the glass phase also penetrates the hollow strut cavities as well as strut cracks. The total porosity of the glass‐coated foams is between 88% and 90%, and the open cellular structure is not negatively affected by the glass coating. The compressive strength increases by a factor of two under consideration of the decrease in total porosity; a compressive strength in the order of magnitude of 2 MPa is feasible. An ion exchange of Na+ by K+ into the glass coating layer (chemical strengthening) is successfully demonstrated, but does not result in an additional improvement of the compressive strength.

Enhancing dispersion stability and recyclability of ceria slurry with polyacrylic acid for improved glass polishing performance

This study aimed to enhance both the dispersion stability and recyclability of micron-sized ceria slurry in glass polishing by incorporating polyacrylic acid (PAA). PAA with a molecular weight of 240 k was very effective as a dispersant for ceria slurry due to its unique surface adsorption and its characteristics as an anionic polyelectrolyte. Using a 240 k-PAA concentration of 1.0 wt% led to significant improvements in polishing performances, as demonstrated by consistent glass removal rates across recycling cycles. Additionally, the study investigated the physico-chemical properties of polishing slurries, such as specific gravity, particle size, zeta potential, and pH. These properties were effectively maintained with the use of PAA as the dispersant, particularly when KOH was used as a pH adjuster. A 100 µm bag-type filtration system was also introduced for handling the micron-sized ceria slurry, highlighting its practical benefits in slurry management. In conclusion, employing 240 k-PAA as a dispersant in micron-sized ceria slurries for Gorilla glass polishing not only maintains quality and stability across recycling cycles but also provides notable economic advantages by enabling the recycling of the slurry.

Retrospective EPR dosimetry in glass and tooth enamel – The methodology and results of MUG group in RENEB 2021 inter-laboratory comparison

Electron Paramagnetic Resonance (EPR) is recognized method in retrospective dosimetry, based on detection of stable paramagnetic centres induced by radiation in biological materials, like enamel, bones, nails, or artificial materials, like glasses and other. EPR dosimetry in glass and enamel were included, in addition to several biological dosimetry tests, in the recent intercomparison project RENEB ILC 2021 as one of the physical dosimetry methods potentially applicable for dose assessment in radiation accidents. EPR group from Medical University of Gdansk (MUG) was one of participants in this intercomparison. The participants reconstructed doses in three blinded samples of watch glass, Gorilla Glass from phone screens and in enamel irradiated with 0 Gy, 1.2 Gy and 3.5 Gy (these doses were revealed after reporting the final results by all participants). For reconstruction of doses in the glass samples the respective calibration samples were provided by organizers of the ILC project. For dosimetry in enamel the participants used their own calibration data. The doses reconstructed by us in the blinded samples (in terms of kerma in air) were: in watch glass: −0.05 Gy, 1.03 Gy, 3.16 Gy, in Gorilla Glass: −0.03 Gy, 1.20 Gy, 3.44 Gy, in enamel: 0.1 Gy, 1.3 Gy, 3.1 Gy. The differences between the reconstructed and the nominal doses were small and the accuracy was sufficient for triage of irradiated people at the level of 1–2 Gy. The small sample mass of the enamel, suitable rather to Q-band EPR dosimetry and potentially available without whole tooth extraction, allowed to obtain satisfactory accuracy of EPR dosimetry also in the X-band measurements.

Gorilla Glass Cutting Using Femtosecond Laser Pulse Filaments

Due to high durability, scratch resistance, and impact resistance, Gorilla glasses are a popular choice for protective screens of smartphones, tablets, and laptops. Precise cutting of Gorilla glasses is very important to maintain the overall aesthetics and user experience, which is very challenging. We demonstrated for the first time the cutting of Gorilla glass by means of femtosecond laser filamentation technique. To achieve laser filamentation, a femtosecond laser beam was focused and irradiated in different depths of the sample Gorilla glasses. The filament length varied with the change in the focus position of the laser beam. The effective numerical aperture of the objective lens rises due to the presence of dielectric material (i.e., the Gorilla glass itself) before the focus position of the femtosecond laser beam inside the glass samples. As a consequence, the focal distance of the incident laser beam was prolonged and focused in a very tiny spot with extremely high energy density. Consequently, filaments (i.e., high aspect ratio micro-voids) were evident inside the Gorilla glass samples. The filament length is controllable by changing the irradiation parameters of the laser beam, including magnification and numerical aperture of the lens, laser energy, and thickness of the Gorilla glass before the target focal point. The filament-engraved Gorilla glass samples go through mechanical cleaving process with 400 MPa pressure on both sides of the laser scanning line for smooth cutting of Gorilla glass. The proposed glass cutting technique show promises for commercial application.

Fs laser written volume Raman–Nath grating for integrated spectrometer on smartphone

In this work we demonstrate the integration of a spectrometer directly into smartphone screen by femtosecond laser inscription of a weak Raman–Nath volume grating either into the Corning Gorilla glass screen layer or in the tempered aluminosilicate glass protector screen placed in front of the phone camera. Outside the thermal accumulation regime, a new writing regime yielding positive refractive index change was found for both glasses which is fluence dependent. The upper-bound threshold for this thermal-accumulation-less writing regime was found for both glasses and were, respectively at a repetition rate less than 150 kHz and 101 kHz for fluence of 8.7 × 106 J/m2 and 1.4 × 107 J/m2. A weak volume Raman–Nath grating of dimension 0.5 by 3 mm and 3 μm pitch was placed in front of a Samsung Galaxy S21 FE cellphone to record the spectrum using the 2nd diffraction order. This spectrometer covers the visible band from 401 to 700 nm with a 0.4 nm/pixel detector resolution and 3 nm optical resolution. It was used to determine the concentration detection limit of Rhodamine 6G in water which was found to be 0.5 mg/L. This proof of concept paves the way to in-the-field absorption spectroscopy for quick information gathering.

Preview the Products on Display at Display Week 2023

Preview the Products on Display at Display Week 2023

The Impact of Different Overlay Materials on the Tactile Detection of Virtual Straight Lines

To improve the perception of haptic feedback, materials and sense-modifier effects should be examined. Teflon, Nylon mesh, and Silicone overlays were tested in combination with lateral vibrations to study their impact on the tactile sense. A feelable point moving along a line was implemented through the use of a dynamically moving interference maximum generated via the offset actuation of four haptic exciters affixed to corners of a Gorilla Glass surface. This feedback was presented to eight participants in a series of randomized experiments. Both the Nylon mesh and Teflon covering revealed a statistically significant (p < 0.05) impact of improvement to the user performance in the task of dynamic haptic virtual straight lines localization. While Silicone covering, having three times greater friction than Gorilla Glass, has less or no impact on both decision time, the number of task repetitions, and error rate (p > 0.05). The lateral vibration modifier (60 Hz) can also successfully be used with an increase in performance by about twofold, at least that was demonstrated for both the Nylon mesh and Teflon covering.

New Phenanthrenyl‐Substituted Hybrid Organic‐Inorganic Polysiloxanes for Optoelectronic Applications

AbstractThe current need for polysiloxanes with high refractive index (RI) is very high because of their importance for optoelectronic applications. To meet this demand, a series of novel polysiloxanes derived from phenanthrenyl‐containing monomers, including the precursor 1‐(9‐phenanthrenyl)‐1,1,4,4,4‐pentamethoxy‐1,4‐disilabutane, are prepared using the sol‐gel technology and free‐radical polymerization. The monomer 1‐(9‐phenanthrenyl)‐1,1,4,4,4‐pentamethoxy‐1,4‐disilabutane is synthezised, purified and fully characterized including 2D‐NMR experiments for the partial assignment of both its1H and13C NMR spectra. The molecular weights of the new three‐dimentional polysiloxanes with variations in their initial molecular compositions are analyzed using gel permeation chromatography (GPC). The polysiloxanes are characterized by1H NMR spectroscopy, and obtained with high RI, thermal stabilities up to 420 °C, and excellent resistance against aging process. The polysiloxanes are coated on silicon‐wafers and gorilla glass substrates using respectively the spin‐ and bar‐coating techniques. The coated glasses show optical transmittance above 91 % with excellent hydrophobic character, refractive indexes up to 1.51, and their CIELAB coordinates are also determined. The effects of the crosslinking agent and packing density of the chains on the chemical, optical and mechanical properties of the polysiloxanes and corresponding films are studied.

Highlights from the Detroit SID Vehicle Display Symposium and Exposition

Highlights from the Detroit SID Vehicle Display Symposium and Exposition

Improvement in measuring losses by interferometric technique for glass waveguides produced by femtosecond laser writing

This study describes a straightforward and non-destructive interferometric technique for measuring the propagation loss in single-mode optical glass waveguides by exploiting a Fabry–Perot cavity effect. The experiment involves coupling a powerful tunable laser source to a single-mode waveguide that is being tested, then using a detector to analyze the transmission fringes of that source after coating the glass end facets with highly reflective coating. Our first experiment, which used a 22.4-mm-long fabricated waveguide on Non-Iox Gorilla glass to demonstrate the technique, resulted in a propagation loss of 0.49 dB/cm at a transmitting wavelength of about 1575 nm, which is completely consistent with the value obtained by a conventional characterization method. The measurement procedure is also independent from the coupling losses, making the characterization easier and reliable after the manufacturing just with a reversible deposition process on the sample under testing.

The unsung hero of the smartphone

James McKenzie reflects on the wonders of Gorilla Glass – an invention that protects billions of smartphones, tablets and laptops around the world from unwanted damage.

Preview the Products on Display at Display Week 2022

Preview the Products on Display at Display Week 2022

Surface nanostructuring of alkali-aluminosilicate Gorilla display glass substrates using a maskless process

This paper reports on the formation of moth-eye nanopillar structures on surfaces of alkali-aluminosilicate Gorilla glass substrates using a self-masking plasma etching method. Surface and cross-section chemical compositions studies were carried out to study the formation of the nanostructures. CF x induced polymers were shown to be the self-masking material during plasma etching. The nanostructures enhance transmission at wavelengths over 525 nm may be utilized for fluid-induced switchable haze. Additional functionalities associated with nanostructures may be realized such as self-cleaning, anti-fogging, and stain-resistance.

High Aspect Ratio Structuring of Glass with Ultrafast Bessel Beams.

Controlling the formation of high aspect ratio void channels inside glass is important for applications like the high-speed dicing of glass. Here, we investigate void formation using ultrafast Bessel beams in the single shot illumination regime. We characterize the morphology of the damages as a function of pulse energy, pulse duration, and position of the beam inside fused silica, Corning Eagle XG, and Corning Gorilla glass. While a large set of parameters allow for void formation inside fused silica, the operating window is much more restricted for Eagle XG and Gorilla glass. The transient formation of a molten layer around voids enables us interpreting the evolution of the morphology with pulse energy and duration.

(Keynote) A Proposed Solution to Li Dendrite Penetration Into Solid Electrolytes

The use of lithium (Li) or sodium (Na) metal anodes together with highly ion-conductive solid electrolytes (SEs) could provide batteries with a step improvement in volumetric and gravimetric energy densities. Unfortunately, these SEs face significant technical challenges, in large part because Li and Na dendrites can penetrate through SEs, leading to short circuits. The ability of such a soft material (Li or Na metal) to penetrate through ceramic is surprising from the point of view of models widely used in the Li-battery field. We introduce a concept, new to the battery field, for preventing penetration of lithium dendrites through SEs by putting the SE surfaces into a state of residual compressive stress. For a sufficiently high compressive stress, cracks have difficulty forming, and cracks that do form are forced to close, inhibiting dendrite penetration. This approach is widely used to solve commercially important stress corrosion cracking problems in metals and static fatigue problems in ceramics and glasses (e.g., Gorilla Glass). However, the technique will not be useful for SEs if the Li-ion transport rate through a SE is substantially reduced when the SE is under compression. Our molecular dynamics calculations for Li-ion transport through a common SE demonstrate that the introduction of even very high residual compressive stresses (10 GPa) has only a modest effect on Li-ion transport kinetics, suggesting that this approach is viable and capable of providing a new paradigm for developing high-performance and mechanically stable SEs. We discuss several possible mechanisms for establishing high residual compressive stresses, including ion implantation and ion exchange. Preliminary results are highly promising.

Al2O3 coated glass by aerosol deposition with excellent mechanical properties for mobile electronic displays

Al2O3 thin film was deposited on Gorilla glass using an aerosol deposition method to improve the mechanical property of cover glass for mobile electronic device. The deposited Al2O3 film (approximately 1 μm thick) was a polycrystalline structure and showed a high light transmittance of approximately 90% in the visible light region. The CIE color space (L*a*b) measurement also showed a characteristic corresponding to the acceptable optical range of the cover glass. Further, it was confirmed that the bending strength improved by 10 %, as compared with bare Gorilla glass (from 6970 kgf/cm2 to 7704 kgf/cm2), and the Vickers hardness increased to approximately 1700–2000 HV, as compared with that of Gorilla glass (<700 HV). Owing to the improved mechanical properties, the Al2O3 thin film exhibited good anti-scratch properties and is expected to be applied to the cover glass of various display products.

Smartphone Screen Integrated Optical Breathalyzer.

One third of fatal car accidents and so many tragedies are due to alcohol abuse. These sad numbers could be mitigated if everyone had access to a breathalyzer anytime and anywhere. Having a breathalyzer built into a phone or wearable technology could be the way to get around reluctance to carry a separate device. With this goal, we propose an inexpensive breathalyzer that could be integrated in the screens of mobile devices. Our technology is based on the evaporation rate of the fog produced by the breath on the phone screen, which increases with increasing breath alcohol content. The device simply uses a photodiode placed on the side of the screen to measure the signature of the scattered light intensity from the phone display that is guided through the stress layer of the Gorilla glass screen. A part of the display light is coupled to the stress layer via the evanescent field induced at the edge of the breath microdroplets. We demonstrate that the intensity signature measured at the detector can be linked to blood alcohol content. We fabricated a prototype in a smartphone case powered by the phone’s battery, controlled by an application installed on the smartphone, and tested it in real-world environments. Limitations and future work toward a fully operational device are discussed.

A Proposed General Solution for Li Dendrite Penetration into Solid Electrolytes

We propose a general solution to the problem of Li dendrite penetration through solid electrolytes such as LLZO. The solution is based on an analogy of Li dendrite penetration to stress corrosion cracking, a process in which a very soft material--water--penetrates through a very hard material--steel--generally at grain boundaries. The problem of stress corrosion cracking was solved many years ago by putting the surface into a state of residual compressive stress. A variety of materials have been strengthened this way, including metals, glasses (e.g., Gorilla glass), and ceramics. However, for this approach to be useful, it is critical, at a minimum, that the presence of a significant residual compressive stress not block ion transport. In this work, we used DFT to show that isotropic compressive residual stresses as high as -10 GPa—the maximum observed in strengthened ceramics—have only a minimal impact on the diffusion rate of Li+ ions through a near-surface region of LLZO. Figure 1

A New General Paradigm for Understanding and Preventing Li Metal Penetration through Solid Electrolytes

Summary The use of lithium (Li) or sodium (Na) metal anodes together with highly ion-conductive solid electrolytes (SEs) could provide batteries with a step improvement in volumetric and gravimetric energy densities. Unfortunately, these SEs face significant technical challenges, in large part because Li and Na dendrites can penetrate through SEs, leading to short circuits. The ability of such a soft material (Li or Na metal) to penetrate through ceramic is surprising from the point of view of models widely used in the Li-battery field. We introduce a concept, new to the battery field, for preventing penetration of lithium dendrites through SEs by putting the SE surfaces into a state of residual compressive stress. For a sufficiently high compressive stress, cracks have difficulty forming, and cracks that do form are forced to close, inhibiting dendrite penetration. This approach is widely used to solve commercially important stress corrosion cracking problems in metals and static fatigue problems in ceramics and glasses (e.g., Gorilla Glass). However, the technique will not be useful for SEs if the Li-ion transport rate through a SE is substantially reduced when the SE is under compression. Our molecular dynamics calculations for Li-ion transport through a common SE demonstrate that the introduction of even very high residual compressive stresses (∼10 GPa) has only a modest effect on Li-ion transport kinetics, suggesting that this approach is viable and capable of providing a new paradigm for developing high-performance and mechanically stable SEs.

Foldable Market Expands with Samsung, Microsoft Offerings

Foldable Market Expands with Samsung, Microsoft Offerings