Thermoplastic Lens Fixing for Optical Sensor Adjustment

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Solution Overview

Problem

Existing optical systems for sensors face challenges in adjusting lenses relative to the lens holder without using adhesives, which introduces manufacturing complexities, increased costs, and recyclability issues, while allowing for continuous adjustment along the optical axis is not feasible without adhesive-related drawbacks.

Innovation Solution

An optical system utilizing thermoplastic fixing elements that reshape to secure the lens in a desired position along the optical axis, eliminating the need for adhesives and allowing continuous adjustment, with thermoplastic fixing elements that can be reshaped to fix the lens securely without interrupting production and ensuring reliability over the system's lifespan.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If adhesive is used to fix the lens to the lens holder, then the lens can be adjusted to a continuous range of positions along the optical axis, but the manufacturing process is interrupted for a longer period due to adhesive hardening time

Engineering Contradiction:
Improveadjustment range of lens positionVSAvoidproduction continuity
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent changes the physical state of the fixing element by heating it above its glass transition temperature to make it deformable, allowing the lens to be positioned continuously along the optical axis. After positioning, the element cools and solidifies to fix the lens in place, eliminating the need for adhesive hardening time and enabling continuous production.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The fixing element undergoes a phase transition from solid to deformable state when heated above its glass transition temperature, and then back to solid state upon cooling. This phase transition allows the element to be reshaped during assembly to achieve continuous lens positioning, then locks the position without requiring adhesive hardening time, thus maintaining production continuity.

Inventive Principle:
Principle #36Phase transitions

2Adaptability or versatility

If adhesive is used to fix the lens, then the lens can be adjusted relative to the lens holder, but foreign material is introduced making recycling more difficult

Engineering Contradiction:
Improvelens adjustabilityVSAvoidrecyclability
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent removes adhesive (foreign material) from the system and replaces it with a thermoplastic fixing element that is either integrated into the lens holder or lens. This eliminates the need for chemical adhesives, making the system easier to recycle while maintaining the ability to adjust lens position through thermal deformation of the fixing element.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The fixing element is made from the same thermoplastic material as the lens holder or lens, creating a homogeneous structure without foreign adhesive materials. This homogeneity simplifies recycling processes while still allowing lens adjustment through controlled thermal deformation of the unified material structure.

Inventive Principle:
Principle #33Homogeneity

3Adaptability or versatility

If adhesive is used to fix the lens, then the lens can be positioned continuously, but adhesives suffer from aging effects reducing reliability

Engineering Contradiction:
Improvecontinuous positioning capabilityVSAvoidservice life
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent replaces adhesive with a thermoplastic fixing element whose mechanical properties can be controlled through temperature parameters. The element remains deformable above its glass transition temperature for positioning, then solidifies upon cooling to provide reliable, long-term fixation without the aging effects that plague adhesives, ensuring both continuous positioning capability and enhanced reliability.

Inventive Principle:
Principle #35Parameter changes

4Ease of manufacture

If a locking element is used to fix the lens, then assembly is simple, but the lens cannot be adjusted relative to the lens holder

Engineering Contradiction:
Improveassembly simplicityVSAvoidlens adjustability
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent transforms the static locking element into a dynamic thermoplastic fixing element that can change its properties based on temperature. The element is deformable when heated, allowing lens adjustment, and becomes rigid when cooled, providing secure fixation. This dynamic behavior combines the assembly simplicity of locking elements with the adjustability previously only achievable with adhesives.

Inventive Principle:
Principle #15Dynamics

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

Enables continuous production without adhesive hardening, reduces production costs, and ensures reliable lens positioning and fixation without material introduction, allowing for modular use and easy adaptation to specific requirements.

Implementation Method 1

a thermoplastic fixing element (7, 7a, 7b, 7c, 7d) for fixing the lens (3) in a desired relative position by thermoplastic reshaping of the fixing element

Methodology Applied
Scientific EffectGlass transition:

Implementation Method 2

The cooling time, during which the thermoplastic fixing element cools down and becomes solid again, is comparatively short and does not interrupt production or interrupts it only briefly

Methodology Applied
Scientific EffectGlass transition:

Data Source

PatentEP2722701B1Optical system for a sensor
Publication Date: 2019.03.13 BAUMER ELECTRIC AG
  • EP2722701B1 patent drawingFigure 1
  • EP2722701B1 patent drawingFigure 2
  • EP2722701B1 patent drawingFigure 3

AI summary

The optical system (1) has lens holder that is provided for holding lens (3) in continuous area of relative position along optical axis (8) of the lens holder. Thermoplastic fixing elements (7,7a) are provided for fixing the lens in desired position by thermoplastic deformation of the fixing elements. Independent claims are included for the following: (1) a sensor; and (2) a method for fixing lens on lens holder in optical system.