Polymer Particle Lubricant for Hermetic Window Sealing

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Solution Overview

Problem

Current window sealing techniques for optical measurement probes, such as elastomeric and metal seals, face challenges in achieving high hermeticity, temperature resistance, and chemical compatibility, particularly in life science applications, where contamination and thermal stress issues arise.

Innovation Solution

A method involving a lubricant with polymer particles suspended in a volatile, low viscosity carrier fluid is applied to the window and aperture, allowing for intimate mechanical contact and filling interstitial voids, reducing friction and stress during the pressing process, while maintaining a hermetic seal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If compression bonding is used to seal the window into the probe body, then hermetic sealing and chemical compatibility are improved, but the pressing forces required may cause shear stresses that fracture the window

Engineering Contradiction:

Improvehermetic sealingVSAvoidwindow retention

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

A lubricant is introduced as an intermediary substance between the window and the probe body housing during the compression bonding process. This lubricant reduces friction and allows the window to be pressed into place with lower forces, preventing window fracture while still achieving hermetic sealing. The lubricant mediates the interaction between the window and housing, enabling the sealing process to proceed without excessive stress on the window.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If higher pressing forces are applied to ensure window retention, then hermeticity is improved, but the window may fracture due to excessive shear stresses

Engineering Contradiction:

ImprovehermeticityVSAvoidwindow fracture

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The lubricant serves as a mediator that reduces the harmful effect of high pressing forces. By introducing this intermediate substance, the system can achieve the necessary hermetic sealing without directly applying excessive force that would cause window fracture. The lubricant absorbs and redistributes the pressing forces, preventing concentration of stress at critical points on the window.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Temperature

If brazing is used to seal the window, then temperature resistance and hermeticity are improved, but thermal stresses between the window and probe body increase

Engineering Contradiction:

Improvetemperature resistanceVSAvoidthermal stress

Core Design Contradiction:

TemperatureVSStress or pressure

Solution Approach 1:

The patent replaces the thermal bonding process (brazing) with a mechanical compression bonding process. Instead of using heat to join the window to the probe body, the invention uses mechanical pressing forces applied at lower temperatures. This substitution eliminates the thermal cycle that causes thermal stress and potential damage to the window and probe body materials.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Ease of manufacture

If compression bonding is used without lubrication, then manufacturing simplicity is improved, but the pressing forces required increase, potentially causing window damage

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidpressing force

Core Design Contradiction:

Ease of manufactureVSForce

Solution Approach 1:

The lubricant is applied as a simple intermediate step in the manufacturing process. It can be applied in various forms (liquid, gel, or pre-coated on components) and requires minimal additional equipment or process complexity. The lubricant layer is thin and does not significantly add to the assembly time or cost, while dramatically reducing the pressing forces needed to achieve hermetic sealing.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 approach enables a robust, temperature-resistant, and chemically compatible seal with reduced pressing forces, preventing contamination and thermal stress, and ensuring reliable retention of the window without fracturing, thus addressing the limitations of existing techniques.

Implementation Method 1

pressing the window into the aperture in the body such that the carrier fluid evaporates, leaving the polymer particles to fill interstitial surface voids

Methodology Applied

Scientific EffectEvaporation: Evaporation

Implementation Method 2

applying a lubricant that includes polymer particles to at least the sidewall of the window or the sidewall of the aperture

Methodology Applied

Scientific EffectLubrication: Lubrication

Data Source

PatentUS11466228B1Friction control and captive sealant for pressed windows

Publication Date: 2022.10.11 ENDRESSHAUSER OPTICAL ANALYSIS INC

AI summary

An improved method of sealing a window into an aperture in a body uses a lubricant comprising polymer particles suspended in a volatile, low viscosity, low surface tension carrier fluid. The carrier fluid is applied to one or both of the sidewalls of the window and aperture, and the window is pressed into the aperture such that the carrier fluid evaporates, leaving the polymer particles to fill interstitial surface voids, while enabling the sidewall of the window to make intimate mechanical contact with the sidewall of the aperture. While having broader application, the present disclosure finds particular utility in optical characterization techniques based upon the Raman effect and fluorescence probes used in process monitoring and control.