Diffractive Optical Ruler for In-Situ Surgical Measurement

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Solution Overview

Problem

In minimally invasive surgeries, it is challenging for surgeons to accurately determine the sizes of organs and tissues due to the instability and complexity of existing in-situ surgical metrology methods, which often require moving parts and rapidly changing projection images.

Innovation Solution

A system and method utilizing a light source with diffractive circle and cross pattern generators, emitting overlapping patterns with different angular divergency, mounted on a surgical instrument to serve as an optical ruler for precise measurements without moving parts, allowing for stable focus and accurate dimension assessment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If moving parts and rapidly changing projection images are used for in-situ surgical metrology, then measurement capability is provided, but focus stability and image clarity deteriorate

Engineering Contradiction:
Improvemeasurement capabilityVSAvoidfocus stability
Core Design Contradiction:
Measurement precisionVSStability of the object's composition

Solution Approach 1:

The patent replaces moving mechanical parts with a stationary optical system that uses diffractive optical elements to generate measurement patterns. The system uses fixed projectors that emit light patterns with different angular divergencies, eliminating the need for moving parts while maintaining measurement capability through optical interference patterns.

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

Solution Approach 2:

The system changes the angular divergency parameter of projected light patterns to create stable interference patterns. By projecting multiple patterns with different angular divergencies from stationary sources, the system achieves focus stability and measurement precision without requiring moving parts or rapidly changing projections.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If complex in-situ surgical metrology methods with moving parts are used, then measurement function is achieved, but device complexity increases

Engineering Contradiction:
Improvemeasurement functionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent eliminates complex mechanical moving parts by using stationary optical projectors with diffractive elements. The measurement function is achieved through optical interference of stationary light patterns rather than mechanical movement, significantly reducing device complexity while maintaining measurement precision.

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

Solution Approach 2:

The system creates optical copies or projections of measurement patterns directly in the surgical field using stationary sources. Instead of physically moving measurement tools, the system projects multiple light patterns that interfere to create measurement information, simplifying the physical device while maintaining measurement capability.

Inventive Principle:
Principle #26Copying

3Measurement precision

If multiple light sources with different angular divergencies are projected, then measurement accuracy is improved, but light energy consumption increases

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidlight energy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent merges multiple light patterns with different angular divergencies into a single integrated measurement system. By combining the interference patterns of multiple stationary light sources, the system achieves high measurement accuracy while using lower individual light energies compared to rapidly changing single-source projections.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system maintains continuous projection of multiple stable light patterns simultaneously rather than rapidly switching between patterns. This continuous action with stationary sources provides sustained measurement accuracy with optimized energy consumption compared to rapidly changing projections that would require higher peak energies.

Inventive Principle:
Principle #20Continuity of useful action

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 real-time, accurate optical measurements within the body cavity, reducing surgery time and cognitive burden, and improving precision by providing a stable and reliable method for determining organ sizes without the need for complex setups or moving parts.

Implementation Method 1

a first pattern generator defining a first longitudinal axis and configured to project a first generated pattern, and a second pattern generator defining a second longitudinal axis and configured to project a second generated pattern. The first and second generated patterns have different angular divergency.

Methodology Applied
Scientific EffectDiffraction: Diffraction

Data Source

PatentEP2777478B1Systems for optical measurement for in-situ surgical applications
Publication Date: 2016.12.14 COVIDIEN LP
  • EP2777478B1 patent drawingFigure 1~2
  • EP2777478B1 patent drawingFigure 3
  • EP2777478B1 patent drawingFigure 4

AI summary

A system and method is presented for performing optical measurements, including a light source configured to emit a light beam, a first pattern generator defining a first longitudinal axis and configured to project a first generated pattern, and a second pattern generator defining a second longitudinal axis and configured to project a second generated pattern. The first and second generated patterns have different angular divergency. The first pattern generator is a diffractive circle pattern generator, whereas the second pattern generator is a diffractive cross pattern generator. Adjustment of the first and second generated patterns with respect to each other cause the system to serve as an optical ruler for performing the optical measurements when the first and second generate patterns overlap or coincide with each other at certain points.