Optical Pathway Blockage Detection Using Threshold Timing

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Solution Overview

Problem

Existing photoelectric sensors in medical devices, such as those used in vitreo-retinal procedures, struggle to accurately determine blockage in optical pathways due to wide voltage output ranges that can cause saturation, leading to ambiguous readings and potential undetected blockages.

Innovation Solution

Implementing techniques that adjust current input and gain in transmitter and receiver circuitry to determine the characteristics of optical pathways by measuring time differences and threshold crossings, allowing for more precise detection of blockage and sensor degradation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If photoelectric sensors are used to detect blockage in optical pathways, then presence/absence of obstruction can be determined, but wide voltage output ranges cause saturation leading to ambiguous readings

Engineering Contradiction:
Improveblockage detection accuracyVSAvoidreading reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The system dynamically adjusts the gain of the receiver circuitry based on the detected light intensity. When the optical pathway is clear, the gain is reduced to prevent saturation of the voltage output. When blockage is detected, the gain is increased to maintain sensitivity. This dynamic gain adjustment resolves the contradiction by allowing accurate blockage detection while preventing ambiguous saturated readings.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the electrical parameters (voltage, current, gain) of the photoelectric sensor system based on the detected conditions. By monitoring the voltage output range and adjusting the operating parameters accordingly, the system maintains measurement precision across different blockage conditions while avoiding saturation, thus improving both accuracy and reliability.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If photoelectric sensors monitor fluid path blockage, then obstruction detection is achieved, but sensor degradation and cleanliness monitoring are insufficient

Engineering Contradiction:
Improveobstruction detection accuracyVSAvoidsensor health information
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The system implements a feedback mechanism where the photoelectric sensor continuously monitors the optical pathway and provides information about both blockage and sensor health. The controller analyzes the voltage output characteristics to determine not only the presence of obstructions but also the cleanliness and operational status of the sensor itself. This feedback loop prevents loss of sensor health information by continuously reporting on sensor condition.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The photoelectric sensor system performs self-diagnosis by monitoring its own output characteristics. The controller evaluates the voltage range and response patterns to assess sensor degradation and cleanliness without requiring external inspection. This self-service capability ensures comprehensive monitoring including sensor health status, preventing information loss about sensor condition.

Inventive Principle:
Principle #25Self-service

3Device complexity

If standard photoelectric detection is used, then simple blockage detection is achieved, but severe blockages may go undetected due to saturation

Engineering Contradiction:
Improvedetection system simplicityVSAvoidblockage detection reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The system maintains relative simplicity while improving reliability through dynamic gain adjustment. The controller automatically modifies the receiver gain based on the detected light level, ensuring that the voltage output remains within the optimal detection range. This prevents saturation that would cause severe blockages to go undetected, while keeping the overall system structure simple and manageable.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

By changing the electrical parameters (gain, voltage scaling) based on detected conditions, the system enhances blockage detection reliability without significantly increasing complexity. The adaptive parameter adjustment ensures that even severe blockages produce detectable voltage changes, preventing false negatives while maintaining system simplicity.

Inventive Principle:
Principle #35Parameter 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 accurate and reliable detection of blockage and sensor health in optical pathways, preventing severe blockages by identifying degradation before it occurs, thus ensuring the integrity of medical procedures.

Implementation Method 1

a light detection element to receive the light output and convert the received light output to a voltage output

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentEP4298426B1Method for determining a characteristic of an optical pathway corresponding to a fluid pathway of a medical device
Publication Date: 2026.03.04 ALCON INC
  • EP4298426B1 patent drawingFigure 1
  • EP4298426B1 patent drawingFigure 2
  • EP4298426B1 patent drawingFigure 3A~3B

AI summary

A system (100) configured to determine a characteristic, such as an amount of blockage and/or wellness/decay, of an optical pathway (104) corresponding to a fluid pathway of a medical device is disclosed. Determining the characteristic includes increasing, over a time period that starts at a first time, a current input to a light emitting element, LEE, (108), receiving, by a light detection element (112), an output of the LEE via the optical pathway during the time period, converting, during the time period, the LEE output to a voltage output, determining a second time in the time period when the voltage output crosses a threshold, and determining the characteristic of the optical pathway between the LEE and the light detection element based on a difference between the second time and the first time.