Schott AG
  • Mainz, Germany
Recent publications
In many applications, the spatial refractive index variation – called homogeneity – within a measurement aperture either in one or two directions is important. Typical application examples are prisms in ultra-precision metrology with stability in multiple directions. Large lenses are used in artificial laser guide star systems for atmospheric correction in large telescopes. The challenge of enabling highest refractive index homogeneities requires tight control of all production steps from melting to hot forming and fine annealing. Large optical formats can be produced as singular castings in moulds up to 1.2 m in diameter and 250 mm thickness. Smaller formats are available as blocks produced in dimensions of approx. 250 x 250 x 180 mm3. A more economic and ecologic way is the production of continuous strips of glass up to approx. 500 mm width and 120 mm thickness. Recently SCHOTT has improved the homogeneity of these continuously produced jumbo strips significantly. Now homogeneity of up to H4 quality (2 ppm index maximum variation) can be provided on apertures up to approx. 900 mm x 500 mm. This paper gives an insight overview on the latest results and current state of this topic at the optical glass manufacturer SCHOTT.
A group of the DECHEMA working group “Single‐Use Technology in Biopharmaceutical Manufacture” is investigating the potential use of single‐use systems for cellular agricultural applications. The preliminary results are summarized in this article. In the biopharmaceutical industry, single‐use systems are well established alongside their reusable counterparts. The DECHEMA working group “Single‐Use Technology in Biopharmaceutical Manufacture” is currently investigating whether single‐use systems can also be used for cellular agricultural applications and preliminary results are presented.
Cutting glass to shape with ultra short laser pulses is nowadays a well established industrial process. Pulses with an elongated straight focal volume (line focus) are used to modify the workpiece throughout its entire depth with one single laser shot. At the same time, processed glass is often required to have a seamed or round edge, which usually requires an extra grinding step. Here we demonstrate that curved line foci can be used to combine cutting and edge shaping of glass sheets in one laser process. We reconsider the Airy-Gauss beam for this purpose, and suggest modifications to the beam profile to avoid unwanted effects, in particular an asymmetric laser modification of the glass sheet. We provide a combined experimental and numerical analysis of the laser process, and show a symmetric convex edge created in a 920μm thick glass sheet.
Glass has been shown to be a capable core substrate material for high-frequency applications. In this article, we examine the capabilities of ultra-thin glass as a material that can be used for high-frequency flexible applications. The two stack-ups discussed in the work presented are 60 $\mu \text{m}$ in total thickness with a core glass substrate (Schott AF32) of 30 $\mu \text{m}$ thickness. One stack-up uses 15 $\mu \text{m}$ JSR GT-N01 as a buildup dielectric on each side of the glass and the other uses 15 $\mu \text{m}$ Taiyo Ink photo imageable dielectric (PID). Both stack-ups have been characterized to 110 GHz and have shown to have comparable performance to materials used in this frequency range. This work then focuses on the mechanical characterization of these stack-ups using free arc bending. The free arc bending tests show that both ultra-thin glass stack-ups are suitable for bending applications as the tested samples can bend to a panel separation below 33% of the sample’s total length. This article concludes that the ultra-thin glass stack-ups are suitable for high-frequency flexible applications because the electrical performance is comparable to other high-frequency rigid materials while exhibiting their flexible capabilities.
Piezoelectric force microscopy (PFM) has demonstrated to be a powerful tool to characterize ferroelectric materials. However, extrinsic effects, most notably, those resulting from surface charges, often mask or mirror genuine piezoelectric response, challenging PFM data understanding. The contribution of surface charges to PFM signal is commonly compensated by using appropriate external bias voltage, which is ad-hoc selected and sample dependent. Here, we determine the compensating voltage in thin films of different ferroelectric materials and we compare with the corresponding I-V characteristics recorded using suitable electrodes. It turns out that the sign and magnitude of the bias voltage required to compensate the surface charges are related to the asymmetry of the I-V characteristics. We propose that this relation results from the fact that the semiconducting properties of the material determine both the I-V dependence, and the sign of charged adsorbates. We show how to make use of this correlation to predict the required compensation voltage of a non-ferroelectric material and we show that spurious piezoelectric-like contributions are largely cancelled. The results provide guidelines to mitigate common extrinsic contributions in PFM imaging.
In this chapter the diverse properties of glass are described, especially focused on the application of thin and ultra‐thin (≤ 100 μm) substrates. The first sections give an overview of the most important manufacturing processes and their advantages and disadvantages, followed by a characterization of typical chemical, physical, and mechanical properties. Next, the authors discuss possibilities for surfaces that are as free of both defects and contaminations as possible. Different glass types and the typical applications are presented in detail, including glass ceramics and photosensitive glass. The last section demonstrates the options for new applications by microstructuring with high variability of the structuring features.
Planar high‐refractive‐index glass wafers are the backbone of leading Augmented and Mixed Reality devices. They route the virtual image to the user's eye, while helping to keep the form factor small. While the glass characteristics directly affect fundamental design parameters such as field of view, the optical system of the wafer with its interfaces as a whole determines the image quality. Here we report on latest achievements both on the glass and on the wafer level that allow for significant weight reduction without sacrificing optical performance. Based on a state‐of‐the‐ art two layer device with a refractive index of 1.9, an overall weight reduction >20% is feasible. This creates a basis to drive AR devices from niche applications toward more widespread commercial adoption.
Mechanisms, feedbacks and resulting non-linearity during silicate glass alteration in a hyperalkaline carbonate solution were studied through hyperspectral Raman imaging of heated fluid-cells. Our experimental setup enabled in operando visualization and rate measurements of glass dissolution and secondary phase precipitation, complemented by spectral characterization of the phases involved and semi-quantitative monitoring of the ionic strength of the solution close to the glass interface. After initial congruent dissolution of the Ba-bearing soda-lime boroaluminosilicate glass, the formation of a crystalline, saponite-based surface alteration layer (SAL), as well as subsequent zeolite precipitation, witherite coating, and carbonate precipitation within pore spaces of the saponite layer were observed. Two in operando experiments were conducted at ∼ 90°C for 180 and 260 h that otherwise solely differed in the solution volume (SV) while keeping the surface area constant. The high SV experiment exhibited a transient upward excursion of initial dissolution rates, followed by continuously rapid glass dissolution along with slow SAL growth and sustained oscillations in ionic strength. Contrastingly, in the low SV experiment, glass dissolution monotonically decreased after the onset of rapid SAL growth and no sustained oscillations were observed. We find that growth conditions and resulting properties of the SAL exert dominant, non-linear effects on the evolution of glass dissolution rates. In turn, SAL formation depends on nucleation/growth kinetics and the accumulation of glass-derived solutes at the reaction front. Both, dissolution and precipitation, feedback with solution chemistry and transport processes, together controlling the evolution of the corrosion process. Additionally, fracturing, delamination, and the evolution of surface morphology may affect glass dissolution rates and transport pathways. Such interpretations of decelerating reaction rates in response to the growth of a protective layer are consistent in micro-scale experiments and in outcrop- to global-scale observations, as is the accelerating effect of surface area creation by physical disruption and morphology. Thus, these µm-scale mechanistic insights could help elucidating local to global environmental feedbacks (e.g., erosion or weathering patterns) as well as process dynamics in engineered environments (e.g., nuclear waste disposal) and may assist the improvement predictive models.
No-Touch Transfer (NTT) of pre-sterilised ready-to-use (RTU) containers is an alternative methodology that follows Good Manufacturing Practice (GMP) and Quality Risk Management (QRM) principles. NTT de-bagging ejects contents from secondary bag packaging without direct contact with contents or exposure to an environment that is a lower grade than the zone being entered. The pre-sterilised containers and sterile barriers offer assured sterility at manufacture and are qualified to remain sterile through the supply chain and the stepwise NTT de-bagging process. This eliminates the requirement for in-process material disinfection steps for transfer into Grade A environments. The present article focuses on design qualification of pre-sterilised RTU container packaging, including definition of sterile barriers together with bioburden study data through the supply chain and simulated NTT. It completes a series of EJPPS articles to support peer-reviewed references on NTT. Together, these articles can be defined as end-to-end qualification of the NTT process, demonstrating a high level of assurance that sterility is maintained from manufacture to point of use. Key Words: Aseptic processing, Design qualification, Good Manufacturing Practice (GMP), Life cycle, No-Touch Transfer (NTT), Pharmaceutical packaging, Pre-sterilised containers, Qualification, Quality by Design (QbD), Quality Risk Management (QRM), Ready-to-use (RTU), Supply chain
Interactions between ultrashort laser pulses with intensities larger than 10 13 W/cm 2 and solids during material processing can lead to the emission of X-rays with photon energies above 5 keV, causing radiation hazards to operators. A framework for inspecting X-ray emission hazards during laser material processing has yet to be developed. One requirement for conducting radiation protection inspections is using a reference scenario, i.e., laser settings and process parameters that will lead to an almost constant and high level of X-ray emissions. To study the feasibility of setting up a reference scenario in practice, ambient dose rates and photon energies were measured using traceable measurement equipment in an industrial setting at SCHOTT AG. Ultrashort pulsed (USP) lasers with a maximum average power of 220 W provided the opportunity to measure X-ray emissions at laser peak intensities of up to 3.3 × 10 15 W/cm 2 at pulse durations of~1 ps. The results indicate that increasing the laser peak intensity is insufficient to generate high dose rates. The investigations were affected by various constraints which prevented measuring high ambient dose rates. In this work, a list of issues which may be encountered when performing measurements at USP-laser machines in industrial settings is identified.
In this study, hot‐compression is applied to two multicomponent borosilicate glasses, Borofloat33® (Boro33) and N‐BK7® (N‐BK7), using molecular dynamics simulations. The effects of pressure on elastic properties, surface energy, and fracture toughness (K{IC}) are investigated. It is found that the impact on K{IC} is mainly dominated by the change of Young's modulus under pressure, which is proportional to the relative change in density. Between the two glasses under investigation, K{IC} can be improved more effectively by the hot‐compression process for Boro33, due to its higher concentration of 3‐coordinated boron (B3), which facilitates densification via B3 to B4 conversion under compression. This article is protected by copyright. All rights reserved
Situation faced: SCHOTT, a global player in the specialty glass and glass-ceramics industry, offers a wide variety of products, among which it’s Business Unit Tubing (SCHOTT Tubing) focuses on semi-products for various industries, e.g., pharmaceutical packaging. By enhancing the production quality with initiatives like perfeXion® and dedicated data collection throughout the whole product life cycle, SCHOTT Tubing, driven by a sense of ambition rather than a sense of urgency, strives to shape the digital transformation of its business and the entire industry. Against this backdrop, SCHOTT Tubing launched the first B2B e-commerce platform and strives to leverage this digital infrastructure for creating additional digital services. Yet, exploring innovative digital services poses a significant challenge for established businesses in the B2B context that demand sound methodological guidance.
Glasses can be used as core substrate for panel- and/or wafer-level packaging to achieve heterogeneous integration of chiplets and integrated passives in increasingly complex packages. Glass has a large number of advantages: The stiffness of glass (i) allows manufacturing of highly accurate buildup layers. These buildup layers can have manufacturing precision of 1μm and below on large dies with sizes of 50mm x 50mm and more, needed for antenna in package (AiP) applications and high performance computing (HPC). Special glasses can be made with adjusted thermal expansion (CTE) (ii), either adjusted to silicon or with larger thermal expansion to allow packages with buildup layers of epoxy molds and metallization that see high thermal loads either during manufacturing or during operation. Glasses can also be optimized with very good dielectric properties (iii) and can be utilized in antenna-in-package applications. But most of all, economic glass structuring techniques (iv) which can provide millions of vias and thousands of cut-outs in a glass panel are important and are being developed. SCHOTTs Structured Glass Portfolio FLEXINITY® and related technologies provide an excellent starting point for highly sophisticated structured glass substrates required for Advanced Packaging. The biggest hurdle for a large-scale commercialization of glass panel packaging is industrial readiness along the whole process chain. This is needed, to bring glass panel packaging in applications like IC-packaging, RF-MEMS packaging and medical diagnostics or, in combination with cutouts for fan-out, embedding of active and passive components. In addition, metallization processes with good adhesion, excellent electrical properties and high geometric accuracy for glasses are an important step. In the current manuscript, we review the status and discuss our contribution towards achieving industrial readiness for glass in panel- and wafer-level packaging.
The purpose of this paper is to introduce cross-functional incentives (CFI) as drivers of purchasing-logistics integration (PLI) and supplier integration (SI). Further, the aim of this study is to find out whether better PLI can increase SI and with it, also logistics performance. The authors develop and test a structural equation model with a partial-least-squares algorithm and a bootstrapping mediation analysis using data collected from 87 manufacturing firms in China. CFI significantly foster both PLI and SI. Further, CFI also indirectly increase SI through better PLI, and logistics performance through better SI. Finally, PLI also indirectly increases logistics performance through better SI. The CFI introduced in this study are confined to purchasing and logistics functions. Due to its novelty, the construct used was designed without specifying the nature of the incentives. Further research should analyze different configurations of incentives. The research provides practitioners with implementable means to promote inbound supply chain integration by setting up overlapping reward systems in the purchasing and logistics functions. The paper demonstrates that the lack of purchasing-logistics and supplier integration that exists in practice is a systemic issue rooted in unaligned incentives set for functional managers. It further shows the critical role that purchasing and logistics functions play when aiming to integrate suppliers.
Planar, high refractive glass wafers are the backbone of leading Augmented/Mixed Reality devices. They route the virtual image to the user's eye, while helping to keep the form factor small. While the glass characteristic directly affects fundamental design parameters like Field‐of‐View, the optical system of the wafer with its surfaces and interfaces as a whole determines the image quality. Besides surface quality of the glass itself, the adjacent coatings, such as anti‐reflective coating and polymer coating with a grid structure can significantly contribute to the total optical loss. Here we are reporting on optical losses caused by surface effects and polymer coatings that might lead to disadvantages in key quality parameters, such as contrast, brightness and distortion of the image.
Chalcogenide glasses are amorphous solid materials formed from chalcogen elements bonding with metals to form typically in binary or tertiary compounds. One family of chalcogenide glasses, based on gallium and lanthanum sulphides, possesses properties important for the infrared (IR) window transmissions and IR applications; these include thermal stability, high solubility of rare earth ions, low phonon energy and high laser damage threshold. Efforts have been made to produce new chalcogenide glasses that can extend the IR transmission window further into the IR. Work has led to the successful melting of a selenium-modified gallium lanthanum sulphide (GLS-Se) glass that can transmit up to 15 μm, however these glasses have, to date, only been demonstrated in bulk glass form. We aim to develop processes for the fabrication of chalcogenide optical fiber to exploit the properties of chalcogenide glasses. Several potential applications include sensing for the civil, medical, and military areas, as these materials offer transmission over much of the molecular fingerprint region (2 to 25 μm). The aim of our work is to understand and control the thermal properties and stability of GLS-Se glasses without compromising their optical properties, in order to produce transparent glass rods and demonstrate the feasibility in fabrication for structured optical preforms by extrusion, as the first step to achieve optical fiber from GLS-Se glass.
This chapter discusses thermo‐viscoelasticity as it applies to the response of glass to thermal and mechanical loads in the temperature range of the glass transition. The impact of temperature history on the structure and on macroscopic properties is described by fictive temperatures, the dynamics of which is calculated by the Tool–Narayanaswamy–Moynihan(−Mazurin–Rekhson–Startsev) model. It is shown how the model parameters are determined from differential scanning calorimetry. The simulations of thermal shrinkage and the cooling rate dependence of the refractive index demonstrate the predictive power of the model. As for the response to mechanical loads, common viscoelastic phenomena (elasticity, delayed elasticity, creep, stress relaxation) as well as material models (Maxwell, Kelvin–Voigt, Burger) are presented. The cases of volume‐preserving shear and shape‐preserving compression (or dilatation) are considered. For small strains, both are handled in a similar way. For large dilatational strain, however, the impact on glass properties and dynamics is taken into account by fictive pressures.
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