Ophthalmic Implant Force Sensor Using Interference Dye

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Solution Overview

Problem

Current methods for monitoring forces acting on ophthalmic implants during implantation face challenges in miniaturization, biocompatibility, signal evaluation, and handling, particularly due to the need for mechanical or electronic sensors with associated power supply lines.

Innovation Solution

An ophthalmological implant with a force sensor partially or completely formed from interference dyes that change color in response to forces, allowing for non-contact, optical detection of forces without the need for electrical or mechanical connections, using structural colors based on diffraction principles rather than absorption or fluorescence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mechanical or electronic sensors are used to monitor forces on the implant, then force monitoring capability is achieved, but device complexity and need for power supply lines increases

Engineering Contradiction:
Improveforce monitoring capabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces mechanical or electronic force sensors with an optical sensing system using interference dyes. The interference dye changes its optical properties (color impression) in response to mechanical stress, allowing force monitoring through optical detection rather than mechanical or electronic means. This eliminates the need for complex electronic components and power supply lines while maintaining force monitoring capability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes color changes of interference dyes as a direct indicator of force application. When force is applied to the implant, the interference dye undergoes structural changes that alter its color impression, providing a visual and detectable signal of the magnitude and direction of applied forces without requiring additional sensing hardware.

Inventive Principle:
Principle #32Color changes

2Measurement precision

If amorphous carbon layers are used as strain sensors, then force detection is possible, but biocompatibility and signal evaluation complexity increases

Engineering Contradiction:
Improveforce detectionVSAvoidbiocompatibility
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent employs interference dyes that can be integrated into the implant structure, combining the sensing function with biocompatible materials. The interference dye system provides force detection capability while maintaining biocompatibility, avoiding the harmful effects associated with amorphous carbon layers and complex electronic signal evaluation systems.

Inventive Principle:
Principle #40Composite materials

3Ease of manufacture

If fluorescent dyes are used for force sensing, then color change detection is achieved, but photostability decreases due to chemical degradation

Engineering Contradiction:
Improvecolor change detectionVSAvoidphotostability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent employs interference dyes that produce structural colors through physical interference effects rather than chemical fluorescence. This physical mechanism is inherently more photostable than chemical fluorescence, as it does not involve electronic transitions that lead to chemical degradation. The interference dye maintains its color-changing capability over extended periods under illumination.

Inventive Principle:
Principle #32Color changes

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 precise and reliable monitoring of forces acting on the implant, preventing tissue or implant damage, with adaptable wavelength ranges and high photostability, facilitating easier integration and biocompatibility, and eliminating the need for complex equipment or power supply lines.

Implementation Method 1

The physical principle behind structural colors is therefore not absorption, but diffraction. This phenomenon occurs when light or electromagnetic radiation interacts with periodic structural elements of the interference dye

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 2

The specific wavelength(s) that satisfy this distance condition(s) are scattered by the periodic structural elements, causing the waves to interfere constructively and/or destructively

Methodology Applied
Scientific EffectInterference: Interference

Implementation Method 3

The condition of constructive interference depends on the distance between the structural elements (d), the wavelength of the incident light (λ), and the angle of incidence (θ), for which the constructive interference is strongest. This relationship can be described with the formula nλ = 2d sin θ (Bragg diffraction)

Methodology Applied
Scientific EffectBragg diffraction: Bragg Diffraction

Data Source

PatentEP4257081B1Ophthalmological implant comprising a base body and a force sensor and device for determining a force acting on an ophthalmological implant
Publication Date: 2024.09.18 CARL ZEISS MEDITEC AG
  • EP4257081B1 patent drawingFigure 1~4
  • EP4257081B1 patent drawingFigure 5~7
  • EP4257081B1 patent drawingFigure 8

AI summary

The invention relates to an ophthalmic implant (10) comprising a base body (12) and a force sensor (18). The force sensor (18) consists at least partially of at least one interference dye (20), which changes its color appearance depending on a force acting on at least one region of the base body (12). The invention further relates to a device for determining a force acting on at least one region of a base body (12) of such an ophthalmic implant (10).