Derivative works — US Patent 7851394

Defensive Disclosure Document for US Patent 7851394: Fining of Boroalumino Silicate Glasses

Patent Being Disclosed Against: US Patent 7851394, "Fining of boroalumino silicate glasses"
Issue Date: 2010-12-14
Assignee: Corning Inc.
Inventor: Adam J. G. Ellison

This Defensive Disclosure document aims to broaden the prior art landscape surrounding US Patent 7851394, rendering future incremental improvements by competitors as obvious or non-novel. The derivatives presented below are based on a core claim of the patent, specifically Claim 1, which defines an alkali-free glass composition with particular oxide ranges, an Σ[RO]/[Al2O3] ratio, a minimum SnO2 content, and a maximum density.

Core Claim 1 (Abstracted): An alkali-free boroalumino silicate glass comprising specific mole percent ranges for SiO2, Al2O3, B2O3, MgO, CaO, SrO, BaO, characterized by: (a) 1.00 ≤ Σ[RO]/[Al2O3] ≤ 1.25; (b) ≥ 0.01 mole percent SnO2; and (c) a density ≤ 2.41 grams/cm³.

Derivative Variations

1. Material & Component Substitution

Derivative 1.1: Rare Earth Oxide and Zinc Oxide Substitution for SrO/BaO

Enabling Description: An alkali-free boroalumino silicate glass composition is proposed wherein the SrO and BaO components, typically present at ≤ 2.0 mol% and ≤ 0.1 mol% respectively as per Claim 1, are partially or entirely substituted by a combination of at least one rare earth oxide (e.g., La2O3, Y2O3, CeO2) and/or ZnO. The total concentration of these substituted oxides, Σ[REO+ZnO], would range from 0.1 to 2.5 mole percent, while maintaining the overall Σ[RO]/[Al2O3] ratio within the 1.00 to 1.25 range. Specifically, La2O3 can be incorporated at 0.1-1.5 mol% to enhance refractive index and modulus, and Y2O3 at 0.1-1.0 mol% for improved thermal stability. ZnO can be added at 0.1-2.0 mol% to act as a network modifier, influencing viscosity and fining kinetics. The SnO2 content remains ≥ 0.01 mole percent, and the target density is maintained at ≤ 2.41 g/cm³. The fining mechanism relies on SnO2 in conjunction with the altered alkaline earth/substituting oxide balance.

Mermaid Diagram:

classDiagram
    class GlassComposition {
        +SiO2: 64.0-71.0 mol%
        +Al2O3: 9.0-12.0 mol%
        +B2O3: 7.0-12.0 mol%
        +MgO: 1.0-3.0 mol%
        +CaO: 6.0-11.5 mol%
        +SnO2: >= 0.01 mol%
        +Density: <= 2.41 g/cm^3
        +SumRO_Al2O3_Ratio: 1.00-1.25
    }
    class SubstitutedOxides {
        +La2O3: 0.1-1.5 mol%
        +Y2O3: 0.1-1.0 mol%
        +ZnO: 0.1-2.0 mol%
        +Total_Subst: 0.1-2.5 mol%
    }
    GlassComposition "1" -- "0..2" SubstitutedOxides : substitutes for SrO/BaO

Derivative 1.2: Cerium Oxide and Mechanical Bubbling Fining

Enabling Description: This derivative utilizes the core glass composition of Claim 1, but replaces or augments the SnO2 fining agent with Cerium Oxide (CeO2) in combination with mechanical bubbling. The CeO2 concentration would be in the range of 0.05 to 0.5 mole percent. During the fining stage, after initial melting, high-purity inert gas (e.g., N2 or Ar) is injected directly into the molten glass through ceramic bubblers at a rate of 0.1 to 1.0 liters per minute per ton of glass. This mechanical agitation, coupled with the redox fining action of CeO2, facilitates the growth and removal of gaseous inclusions. The process is conducted within the specified Σ[RO]/[Al2O3] ratio of 1.00-1.25 to optimize meltability and gas solubility.

Mermaid Diagram:

flowchart TD
    A[Batch Materials] --> B{Melt Glass};
    B --> C{Adjust Composition & Σ[RO]/[Al2O3] Ratio};
    C --> D[Add CeO2 Fining Agent];
    D --> E{Mechanical Bubbling};
    E -- Inert Gas Injection --> F[Bubble Coalescence & Rise];
    F --> G{Fined Glass Melt};
    G --> H[Form Glass Sheet];

Derivative 1.3: Germanium Oxide Partial Substitution for Silicon Dioxide

Enabling Description: A derivative glass composition maintains the alkali-free nature and the core ranges of Al2O3, B2O3, MgO, CaO, SrO, and BaO from Claim 1, but introduces GeO2 as a partial substitute for SiO2. The SiO2 concentration is reduced to 60.0-70.0 mole percent, and GeO2 is incorporated at 0.5 to 4.0 mole percent. This substitution is performed while preserving the Σ[RO]/[Al2O3] ratio between 1.00 and 1.25. GeO2 acts as a glass former, similar to SiO2, but can influence refractive index, density (potentially increasing it, requiring careful balance to meet ≤ 2.41 g/cm³), and melt viscosity. The fining continues to utilize SnO2 at ≥ 0.01 mole percent, with the inherent enhancement provided by the controlled Σ[RO]/[Al2O3] ratio.

Mermaid Diagram:

classDiagram
    class BaseGlass {
        +SiO2: 64.0-71.0 mol%
        +Al2O3: 9.0-12.0 mol%
        +B2O3: 7.0-12.0 mol%
        +MgO: 1.0-3.0 mol%
        +CaO: 6.0-11.5 mol%
        +SrO: 0-2.0 mol%
        +BaO: 0-0.1 mol%
        +SnO2: >= 0.01 mol%
        +SumRO_Al2O3_Ratio: 1.00-1.25
        +Density: <= 2.41 g/cm^3
    }
    class DerivativeGlass {
        +SiO2: 60.0-70.0 mol% (reduced)
        +GeO2: 0.5-4.0 mol% (added)
        +Al2O3: 9.0-12.0 mol%
        +B2O3: 7.0-12.0 mol%
        +MgO: 1.0-3.0 mol%
        +CaO: 6.0-11.5 mol%
        +SrO: 0-2.0 mol%
        +BaO: 0-0.1 mol%
        +SnO2: >= 0.01 mol%
        +SumRO_Al2O3_Ratio: 1.00-1.25
        +Density: <= 2.41 g/cm^3 (controlled)
    }
    BaseGlass --|> DerivativeGlass : extends with GeO2

2. Operational Parameter Expansion

Derivative 2.1: Ultra-Thin Glass Production with Controlled Micro-Downdraw

Enabling Description: This derivative focuses on producing ultra-thin glass sheets (< 50 µm, e.g., 10-30 µm) from the glass composition of Claim 1 using a modified downdraw process. The molten glass, with its defined Σ[RO]/[Al2O3] ratio (1.00-1.25) and SnO2 fining, is fed into a specialized micro-fusion draw machine where the slot width of the isopipe is reduced to 0.5-2.0 mm. The draw speed is precisely controlled at a lower rate (e.g., 0.1-1.0 m/min) compared to standard fusion processes, allowing for greater thinning without excessive necking. An array of localized chilling jets (e.g., compressed air or nitrogen) is positioned immediately below the draw point to rapidly increase glass viscosity, preventing sag and ensuring dimensional stability at extreme thinness. The temperature profile along the isopipe is tightly managed to maintain the liquidus viscosity > 100,000 poises and facilitate efficient fining.

Mermaid Diagram:

flowchart TD
    A[Molten Glass Feed] --> B{Micro-Isopipe (0.5-2.0mm slot)};
    B --> C[Controlled Draw Speed (0.1-1.0 m/min)];
    C --> D{Localized Chilling Jets};
    D --> E[Ultra-Thin Glass Sheet (<50µm)];
    subgraph Fining Zone
        B -- Σ[RO]/[Al2O3] + SnO2 --> B
    end
    subgraph Thermal Control
        B -- Temp Profile --> C
    end

Derivative 2.2: High-Temperature, Plasma-Assisted Melting and Fining

Enabling Description: The boroalumino silicate glass of Claim 1 is subjected to a high-temperature, plasma-assisted melting and fining process. Batch materials are introduced into a plasma furnace operating at temperatures exceeding 1700°C, potentially up to 2000°C. This extreme thermal environment, generated by induction plasma or transferred arc plasma, ensures rapid dissolution of refractory components and significantly accelerates the fining process. The high temperature allows for a slight expansion of the SiO2 range (up to 72.0 mol%) while maintaining meltability. The inherent high gas diffusivity in the plasma-superheated melt, combined with the SnO2 fining agent (≥ 0.01 mole percent) and the optimized Σ[RO]/[Al2O3] ratio (1.00-1.25), ensures efficient removal of gaseous inclusions. This process reduces residence time requirements and allows for faster throughput.

Mermaid Diagram:

flowchart TD
    A[Batch Materials] --> B{Plasma Furnace (>1700°C)};
    B -- High Heat Flux --> C[Rapid Dissolution & Melting];
    C --> D{Enhanced Gas Diffusion};
    D -- SnO2 Fining + Σ[RO]/[Al2O3] Effect --> E[Accelerated Bubble Removal];
    E --> F[Homogeneous Fined Melt];
    F --> G[Glass Forming];

Derivative 2.3: Cryogenic Post-Fining for Micro-Bubble Removal

Enabling Description: Following conventional melting and SnO2 fining of the Claim 1 glass composition, a supplementary cryogenic post-fining step is introduced for the removal of residual micro-bubbles (e.g., < 50 µm diameter). After the primary fining stage, but before final forming, the molten glass stream is briefly exposed to a localized, controlled cooling zone (e.g., using liquid nitrogen or helium jets) which rapidly reduces the glass temperature by 50-100°C. This sudden temperature drop induces transient thermal stresses that can cause micro-bubbles to coalesce or precipitate out as dissolved gases become supersaturated. The glass is then re-heated slightly to restore working viscosity for the final downdraw process. This method exploits the temperature dependence of gas solubility and surface tension to enhance micro-defect removal.

Mermaid Diagram:

sequenceDiagram
    participant GM as Glass Melt
    participant PF as Primary Fining (SnO2, ΣRO/Al2O3)
    participant CZ as Cryogenic Zone
    participant RW as Re-Heating/Working
    participant GF as Glass Forming

    GM->>PF: Melt & Fining
    PF->>CZ: Molten Glass Stream
    CZ->>CZ: Rapid Cooling (50-100°C drop)
    CZ->>CZ: Micro-Bubble Coalescence/Precipitation
    CZ->>RW: Reheat to Working Temp
    RW->>GF: Final Forming

3. Cross-Domain Application

Derivative 3.1: High-Temperature Aerospace Window Substrates

Enabling Description: The alkali-free boroalumino silicate glass of Claim 1, with its low CTE (28-34 × 10⁻⁷ /°C) and high strain point (> 650°C), is adapted for use as high-temperature transparent window substrates in aerospace applications, such as hypersonic vehicles or re-entry capsules. The glass is formulated within the specified compositional ranges, with SnO2 fining and optimized Σ[RO]/[Al2O3] ratio, to achieve a density ≤ 2.41 g/cm³ for weight reduction. The glass sheets are produced by a fusion downdraw process to ensure pristine surface quality and minimal internal stress (< 150 psi). These substrates are further thermally tempered or chemically strengthened post-forming to withstand extreme thermal gradients and aerodynamic stresses experienced at high Mach numbers or during atmospheric re-entry.

Mermaid Diagram:

flowchart TD
    A[Claim 1 Glass Composition] --> B{Fusion Downdraw};
    B -- Pristine Surface, Low Stress --> C[Glass Sheet];
    C --> D{Thermal Tempering / Chemical Strengthening};
    D --> E[Aerospace Window Substrate];
    E -- Withstand Thermal Gradients & Stress --> F[High-Speed Aircraft/Spacecraft];

Derivative 3.2: Substrates for High-Efficiency Multi-Junction Solar Cells

Enabling Description: The alkali-free boroalumino silicate glass described in Claim 1 is employed as a substrate for multi-junction concentrated photovoltaic (CPV) solar cells. The glass's low alkali content (≤ 0.1 mol%) is critical to prevent ion diffusion that degrades semiconductor performance during high-temperature deposition processes (e.g., MOCVD of III-V materials at 500-700°C). The controlled CTE (28-34 × 10⁻⁷ /°C) minimizes stress mismatch with subsequent active layers. The glass is fined using SnO2 (≥ 0.01 mole percent) in conjunction with the Σ[RO]/[Al2O3] ratio (1.00-1.25) to ensure optical clarity, maximizing light transmission and minimizing scattering from gaseous inclusions. This enables high performance and long-term stability of the solar cells.

Mermaid Diagram:

classDiagram
    class GlassSubstrate {
        +Composition: Claim 1 (low alkali)
        +CTE: 28-34x10^-7 /°C
        +StrainPoint: >= 650°C
        +OpticalClarity: High
    }
    class SolarCellMfg {
        +HighTempDeposition: MOCVD (500-700°C)
        +MultiJunctionLayers: III-V Semiconductors
        +ConcentratorOptics: Integrated
    }
    GlassSubstrate --> SolarCellMfg : Provides foundation
    SolarCellMfg --> HighPerformanceCPV : Enables high efficiency

Derivative 3.3: Microfluidic Lab-on-a-Chip Devices

Enabling Description: The alkali-free boroalumino silicate glass of Claim 1, known for its chemical durability and precision formability via downdraw processes, is utilized for fabricating advanced microfluidic lab-on-a-chip devices. The glass composition, with its specified Σ[RO]/[Al2O3] ratio (1.00-1.25) and SnO2 fining, ensures a high-quality, defect-free material for photolithographic patterning and subsequent wet chemical etching to create intricate microchannels and reaction chambers. The excellent chemical durability provides resistance to various biological reagents and buffers (e.g., pH 2-10). The low CTE is advantageous for precise alignment and bonding of multiple glass layers or integration with other materials (e.g., silicon for sensors). The fusion-formed glass surfaces are inherently smooth (Ra < 0.5 nm), crucial for minimizing non-specific adsorption and ensuring predictable fluid flow in microchannels.

Mermaid Diagram:

flowchart TD
    A[Claim 1 Glass Composition] --> B{Fusion Downdraw};
    B -- Smooth Surface, Chemical Durability --> C[Glass Substrate];
    C --> D{Photolithography & Wet Etching};
    D --> E[Microchannels & Chambers];
    E --> F[Layer Bonding];
    F --> G[Microfluidic Lab-on-a-Chip Device];

4. Integration with Emerging Tech

Derivative 4.1: AI-Driven Adaptive Fining Optimization

Enabling Description: An AI-driven system dynamically optimizes the fining process for the glass composition of Claim 1. Real-time sensor data (e.g., optical inclusion count, melt temperature, viscosity, redox potential in the melter, and raw material impurity analysis) is continuously fed into a machine learning model. This model, trained on historical production data and thermodynamic simulations, predicts the optimal adjustments to the SnO2 concentration (within its specified range ≥ 0.01 mole percent), melt temperature, and residence time to maintain a target gaseous inclusion level (< 0.05 inclusions/cm³). The AI system adaptively fine-tunes parameters, including minor adjustments to CaO/MgO/Al2O3 ratios within the Claim 1 bounds to dynamically control the Σ[RO]/[Al2O3] ratio (1.00-1.25) for optimal fining efficiency, even with variations in batch material quality.

Mermaid Diagram:

graph TD
    A[Raw Material Analysis] --> B{Melt Process Sensors};
    B --> C[Optical Inclusion Monitor];
    D[AI/ML Optimization Engine];
    A & B & C --> D;
    D -- Adjust SnO2, Temp, Time, minor comp. --> E[Fining Control System];
    E --> F[Glass Melter/Finer];
    F -- Fined Glass --> G[Quality Control];
    G --> C;

Derivative 4.2: IoT-Enabled Real-time Defect Detection and Process Adjustment

Enabling Description: The fusion downdraw process for the Claim 1 glass composition incorporates an array of IoT-enabled optical and ultrasonic sensors placed strategically along the melting, fining, and forming lines. These sensors capture real-time data on gaseous inclusion size and frequency, glass temperature profiles, and molten glass flow characteristics. The data is transmitted wirelessly (e.g., via 5G or Wi-Fi 6) to a central processing unit where edge computing algorithms analyze defect trends. If defect levels exceed predefined thresholds, an automated feedback loop adjusts process parameters such as the fining agent feed rate (SnO2), specific energy input to the melter, or local atmospheric conditions above the melt surface. This system proactively mitigates defect formation before glass sheets are fully formed, minimizing waste and ensuring consistent quality.

Mermaid Diagram:

sequenceDiagram
    participant SensorArray as IoT Sensors (Optical, Ultrasonic)
    participant EdgeGateway as Edge Computing Gateway
    participant CentralCPU as Central Processing Unit
    participant FiningControl as Fining Control System
    participant GlassProcess as Glass Melting & Fining

    SensorArray->>EdgeGateway: Stream Real-time Defect Data
    EdgeGateway->>CentralCPU: Aggregated Data (Low Latency)
    CentralCPU->>CentralCPU: Analyze Defect Trends (AI/ML)
    alt Defect Threshold Exceeded
        CentralCPU->>FiningControl: Send Adjustment Commands
        FiningControl->>GlassProcess: Adjust SnO2 Feed, Temp, Air Flow
    else Within Tolerance
        CentralCPU->>CentralCPU: Continue Monitoring
    end
    GlassProcess-->>SensorArray: Produces Glass (feedback loop)

Derivative 4.3: Blockchain-Verified Glass Pedigree for High-Security Displays

Enabling Description: For specialized display applications requiring stringent material provenance (e.g., secure government displays, medical imaging), the manufacturing process of the Claim 1 boroalumino silicate glass is integrated with a blockchain-based supply chain verification system. Each batch of raw materials (SiO2, Al2O3, B2O3, MgO, CaO, SrO, BaO, SnO2) has its origin, purity certificates, and supplier data immutably recorded as a transaction on a private blockchain ledger. During the melting and fining of the glass, critical process parameters (e.g., melt temperature, fining agent addition rates, Σ[RO]/[Al2O3] ratio adherence, measured defect rates, and final density verification) are recorded as subsequent transactions. This provides an unalterable, transparent record of the entire manufacturing history, enabling end-to-end traceability of the glass substrates from raw material to finished display, enhancing quality assurance and countering counterfeiting.

Mermaid Diagram:

flowchart TD
    A[Raw Material Supplier] --> B{Purity Certificates & Batch IDs};
    B --> C[Blockchain Ledger];
    D[Glass Manufacturer];
    C -- Record Matl Data --> D;
    D -- Melter/Finer Logs --> E{Process Parameters};
    E --> C;
    F[Quality Control & Final Properties];
    F --> C;
    C -- Verified Pedigree --> G[High-Security Display Manufacturer];
    G --> H[End Product (Blockchain-Verified)];

5. The "Inverse" or Failure Mode

Derivative 5.1: Controlled-Defect Glass for Prototyping and Sacrificial Layers

Enabling Description: This derivative involves intentionally adjusting the glass composition of Claim 1, or its fining parameters, to produce glass sheets with a higher, but controlled and reproducible, level of gaseous inclusions. For example, the SnO2 fining agent concentration could be reduced to below 0.01 mole percent, or even omitted, and/or the Σ[RO]/[Al2O3] ratio could be deliberately shifted to the lower end of the allowed range (closer to 1.00) or even slightly below (e.g., 0.95-0.99) while still maintaining the fundamental boroalumino silicate framework. This "controlled-defect" glass would have a predictable inclusion density (e.g., 0.1-0.5 inclusions/cm³), making it suitable for cost-effective prototyping of display designs, sacrificial layers in multi-step processing, or non-optical, low-cost substrate applications where pristine optical quality is not required. This process minimizes energy consumption and fining agent usage.

Mermaid Diagram:

graph LR
    A[Claim 1 Base Glass] --> B{Modify Fining Parameters};
    B -- Reduce SnO2 (<0.01 mol%) --> C[Lower Fining Efficiency];
    B -- Shift Σ[RO]/[Al2O3] (<1.00) --> C;
    C --> D[Controlled Inclusion Density (e.g., 0.1-0.5/cm³)];
    D --> E[Prototyping Substrate];
    D --> F[Sacrificial Layer];
    D --> G[Low-Cost Non-Optical Application];

Derivative 5.2: Low-Energy Fining for Recycled Cullet Streams

Enabling Description: The invention's glass composition (Claim 1) is adapted for a low-energy fining process specifically optimized for high-percentage recycled glass cullet streams (e.g., 50-90% cullet). The intrinsic fining provided by the Σ[RO]/[Al2O3] ratio (1.00-1.25) is exploited, allowing for a reduced concentration of SnO2 (e.g., 0.01-0.05 mole percent, or even trace amounts from cullet contamination). The melting temperature is lowered to the practical minimum (e.g., 1580-1600°C), reducing energy input. While this may result in a slightly higher, but acceptable, gaseous inclusion level (e.g., 0.05-0.1 inclusions/cm³), the primary objective is environmental sustainability through increased cullet utilization and reduced energy consumption. The resultant glass retains key physical properties such as density (≤ 2.41 g/cm³) and CTE for moderate display or architectural glass applications.

Mermaid Diagram:

flowchart TD
    A[High Cullet Input (50-90%)] --> B{Batching & Melting (1580-1600°C)};
    B --> C{Reduced SnO2 Fining (0.01-0.05 mol%)};
    C -- Leverage Σ[RO]/[Al2O3] --> D[Fining Process];
    D --> E[Glass Sheet (acceptable inclusion level)];
    E -- Low Energy, High Recycled Content --> F[Sustainable Glass Product];

Derivative 5.3: Bio-Resorbable Boroalumino Silicate Glass for Medical Implants

Enabling Description: A bio-resorbable version of the boroalumino silicate glass, based on the alkali-free framework of Claim 1, is developed for temporary medical implant applications where controlled degradation is desired. This involves modifying the B2O3 content (e.g., increasing to 10.0-15.0 mole percent) and potentially introducing P2O5 (e.g., 0.5-3.0 mole percent) as an additional glass former, while carefully adjusting the alkaline earth oxides (MgO, CaO, SrO) to maintain the Σ[RO]/[Al2O3] ratio within or slightly above the claimed range (e.g., 1.00-1.30) to facilitate melting and fining with SnO2 (≥ 0.01 mole percent). The increased B2O3 and P2O5 promote hydrolytic degradation in physiological environments. The fining process ensures minimal inclusions, critical for biocompatibility. The glass's resorbable nature makes it suitable for bone scaffolds, drug delivery matrices, or temporary biosensors, where it degrades into benign components over time.

Mermaid Diagram:

stateDiagram-v2
    state "Initial Glass Composition (Claim 1 Base)" as InitComp
    state "Modified Composition (Bio-Resorbable)" as ModComp
    state "Fining Process (SnO2, ΣRO/Al2O3)" as Fining
    state "Glass Forming (Medical Grade)" as Forming
    state "Sterilization & Implantation" as Implant
    state "In Vivo Degradation" as Degradation
    state "Resorbed Components" as Resorbed

    InitComp --> ModComp : Increase B2O3, Add P2O5, Adjust RO
    ModComp --> Fining : Ensure minimal inclusions
    Fining --> Forming : High-purity product
    Forming --> Implant : Application in medical field
    Implant --> Degradation : Controlled bio-resorption
    Degradation --> Resorbed : Biodegradable over time

Combination Prior Art Scenarios

These scenarios combine the teachings of US7851394 (specifically the glass composition and fining methods) with existing open-source or widely adopted industry standards, making certain future improvements or applications obvious.

Combination with ASTM Standards for Glass Characterization:
- Disclosure: The boroalumino silicate glass compositions and fining methods taught by US7851394 (e.g., Claim 1, defining specific oxide ranges, Σ[RO]/[Al2O3] ratio, SnO2 content, and density) are explicitly designed to achieve certain physical properties, including thermal expansion coefficient (CTE) and strain point. The measurement and verification of these properties are routinely performed using widely adopted, publicly available standards. Specifically, determining the linear coefficient of thermal expansion (CTE) over the temperature range 0-300°C as per the patent's disclosure is a standard procedure outlined in ASTM E228 (Standard Test Method for Linear Thermal Expansion of Solid Materials With a Push-Rod Dilatometer). Similarly, the strain point, crucial for thermal stability, is determined by ASTM C336 (Standard Test Method for Annealing Point and Strain Point of Glass by Fiber Elongation). The combination of the specific glass compositions of US7851394 with the standardized, open-access methodologies of ASTM E228 and ASTM C336 for property verification is an obvious and conventional practice for any person skilled in the art of glass manufacturing and characterization.
- Mermaid Diagram:
```
graph TD
    A[US7851394 Glass Composition] --> B{CTE Property (28-34x10^-7 /°C)};
    A --> C{Strain Point Property (>= 650°C)};
    B --> D[ASTM E228: CTE Measurement Standard];
    C --> E[ASTM C336: Strain Point Measurement Standard];
    D & E --> F[Standardized Glass Characterization];
```
Combination with ISA-88 Batch Control Standard for Manufacturing Process Automation:
- Disclosure: The method for producing alkali-free glass sheets described in US7851394 (e.g., as detailed in the Summary of Invention, Third Aspect, comprising selecting, melting, and fining batch materials via a downdraw process, particularly a fusion process) is a batch-oriented manufacturing operation at various stages (batch preparation, melting, fining, forming). The implementation and automation of such complex batch processes are widely standardized by the ANSI/ISA-88 (ISA-88) Batch Control Standard. ISA-88 provides a robust framework for defining physical models (equipment hierarchy), procedural models (recipes, unit procedures, operations, phases), and control activity models for batch manufacturing. Applying ISA-88 principles to structure and automate the batching of raw materials (including fining agents like SnO2), controlling the melting furnace temperature profiles, and managing the fining and conditioning stages in the fusion process for the glass compositions of US7851394 is an obvious application of established industrial automation best practices. This ensures modularity, flexibility, and reproducibility in manufacturing the claimed glasses.
- Mermaid Diagram:
```
graph TD
    A[US7851394 Batch Materials Prep] --> B{ISA-88 Batch Control: Unit Procedures};
    B --> C{ISA-88 Batch Control: Operations (Melting)};
    C --> D{ISA-88 Batch Control: Operations (Fining)};
    D --> E{ISA-88 Batch Control: Phases (Forming)};
    E --> F[US7851394 Fined Glass Sheet];
    style A fill:#f9f,stroke:#333,stroke-width:2px
    style F fill:#f9f,stroke:#333,stroke-width:2px
```
Combination with OPC UA for Real-time Process Data Exchange and Control:
- Disclosure: The continuous monitoring and control of glass melting and fining processes are critical for achieving the low gaseous inclusion levels and precise compositional requirements of the glass described in US7851394. Modern industrial environments rely on open communication standards for interoperability between sensors, control systems, and data analytics platforms. The OPC Unified Architecture (OPC UA) is an open-source, cross-platform standard for secure and reliable data exchange from sensors to cloud applications. Integrating OPC UA servers and clients within the production line for US7851394's glass would enable real-time telemetry of critical parameters, such as melt temperatures, fining agent feed rates (SnO2), optical measurements of inclusion density in the melt, and compositional analysis data. This data can then be securely exchanged with a Supervisory Control and Data Acquisition (SCADA) system or an AI optimization engine (as described in Derivative 4.1) to monitor and adjust the fining efficiency and glass properties in real-time, thereby ensuring consistent production of the claimed boroalumino silicate glasses.
- Mermaid Diagram:
```
sequenceDiagram
    participant Sensors as Process Sensors (Temp, Flow, Inclusions)
    participant OPCS as OPC UA Server
    participant OPUC as OPC UA Client (Control System)
    participant GM as Glass Melter/Finer (US7851394)

    Sensors->>OPCS: Publish Real-time Data (Melter Temp, SnO2 Rate, Inclusion Count)
    OPCS->>OPUC: Subscribe to Data
    OPUC->>OPUC: Analyze Data & Determine Adjustments
    OPUC->>OPCS: Send Control Commands (e.g., Adjust SnO2, Heater Power)
    OPCS->>GM: Implement Control Actions
    GM-->>Sensors: Effect on Glass Production
```