Rotating Cover Optical Instrument for Droplet Evaporation Control

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Solution Overview

Problem

Traditional instruments for measuring optical properties of liquid samples face inaccuracies due to evaporation and variations in drop volume, especially when measuring microliter-sized droplets, as they are sensitive to surface tension forces and gravitational forces, leading to inconsistent results.

Innovation Solution

An optical instrument with a drop-supporting surface on a housing, a rotatable cover with a light source connector, and a sealing mechanism that isolates the droplet from ambient light, maintaining a fixed light source and droplet position for precise measurement, while a surrounding reservoir helps minimize evaporation by creating a saturated atmosphere.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a drop of liquid is deposited on a drophead for optical measurement, then the measurement can be performed on small volumes, but evaporation causes variation in drop volume leading to measurement inaccuracy

Engineering Contradiction:
Improvedrop volumeVSAvoidmeasurement accuracy
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The patent applies preliminary anti-action by introducing a saturating vapor atmosphere before measurement to prevent evaporation. The reservoir containing bulk liquid generates vapor that saturates the chamber atmosphere, counteracting the evaporation tendency of the deposited drop and maintaining constant drop volume throughout the measurement process.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The patent creates an inert environment by establishing a saturated vapor atmosphere within the chamber. This vapor-saturated environment acts as an inert medium that eliminates mass transfer from the drop to the surrounding air, effectively isolating the drop from evaporative losses and maintaining measurement accuracy.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

2Measurement precision

If the light source is positioned close to the drop-supporting surface for accurate illumination, then measurement precision improves, but positioning accuracy is compromised by manual adjustment

Engineering Contradiction:
Improveillumination accuracyVSAvoidpositioning accuracy
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent replaces manual mechanical positioning with an automated motor-driven rotating cover mechanism. The cover rotates to precisely position the light source connector over the drop-supporting surface, eliminating operator-induced positioning variations and ensuring consistent, accurate alignment between the light source and drop for repeated measurements.

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

Solution Approach 2:

The rotating cover mechanism serves multiple functions: it positions the light source connector for accurate illumination, provides a sealed chamber environment through the cover itself, and enables reproducible positioning through rotational indexing. This multi-functional design integrates positioning, sealing, and illumination setup into a single automated operation.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 setup ensures accurate and consistent measurement of optical properties by maintaining the droplet's volume and reducing evaporation, allowing for precise comparison of identical droplets and minimizing operator-induced variations.

Implementation Method 1

a light source received in said connector is positioned to illuminate the drop-supporting surface

Methodology Applied
Scientific EffectLight emission: Light

Implementation Method 2

the surface of the drophead is dimensioned to constrain the drop to adopt a shape which is dominated more by surface tension forces than by gravitational forces

Methodology Applied
Scientific EffectSurface tension: Surface Tension

Implementation Method 3

A particular source of variation in drop volume is a evaporation from the drop between the time when the drop is deposited on the drophead and the time when the measurement is taken

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP2697624B1An optical instrument
Publication Date: 2017.05.31 MCMILLAN NORMAN
  • EP2697624B1 patent drawingFigure 1
  • EP2697624B1 patent drawingFigure 2~3
  • EP2697624B1 patent drawingFigure 4~7

AI summary

An optical instrument has a drop-supporting surface for receiving a droplet of liquid with a cover mounted on the housing which receives a light source and provides communication between the light source and the inner surface of the cover. A loading aperture extending through the cover permits access to the drophead when the cover is in a first rotational loading position, and the cover may be rotated to a measurement position in which the light source is positioned to illuminate the drop-supporting surface. A positioning mechanism provided between the cover and the housing engages the cover when it reaches the measurement position and thereby ensures that the light source and drop-supporting surface are maintained in fixed spaced-apart relationship.