Optical Liquid Level Measurement in Cell Culture

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Solution Overview

Problem

Existing methods for measuring liquid levels in cell culture solutions, such as electric balances and optical sensors, are either bulky and expensive or require multiple sensors, leading to increased size and cost, and are not capable of continuous measurement.

Innovation Solution

A method and apparatus using at least two light beams of different wavelengths to measure absorbance, allowing for continuous liquid level determination and pH measurement in a cell culture solution, utilizing materials like fetal bovine serum and phenol red, which have specific absorption peaks and convergence points, enabling simultaneous measurement of liquid level and pH without increasing apparatus size or cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If an electric balance is used to measure liquid level, then measurement accuracy is improved, but device size and cost increase

Engineering Contradiction:

Improveliquid level measurement accuracyVSAvoidapparatus size and cost

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical weighing system (electric balance) with an optical measurement system. A light emitter sends light through the cell culture solution to a light receiver, and the liquid level is determined based on light absorption characteristics, eliminating the need for bulky mechanical weighing equipment while maintaining measurement accuracy.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the measurement parameter from weight to light absorbance. By measuring how much light is absorbed by the cell culture solution at different wavelengths, the system can determine liquid level without using a mechanical balance, thus reducing device size and cost while preserving measurement precision.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If multiple optical sensors are disposed to detect plural liquid levels, then measurement capability is improved, but device size and cost increase

Engineering Contradiction:

Improveliquid level detection capabilityVSAvoidnumber of sensors and apparatus size

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent makes a single optical sensor system multi-functional by using multiple wavelengths of light. The same light emitter and light receiver can detect different liquid levels by varying the wavelength, and can also measure pH values, eliminating the need for multiple separate sensors for different measurement purposes.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent adds the wavelength dimension to the optical measurement system. Instead of using multiple sensors at different positions, the system uses a single sensor that can operate at multiple wavelengths, transforming the problem from spatial multiplication to spectral multiplication, thereby reducing the number of physical components needed.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Adaptability or versatility

If multiple optical sensors are disposed to detect plural liquid levels, then measurement capability is improved, but measurement continuity deteriorates

Engineering Contradiction:

Improveliquid level detection capabilityVSAvoidmeasurement continuity

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent enables continuous measurement by using a single optical sensor system that can continuously vary wavelengths and measure absorbance. Unlike discrete multi-sensor systems that can only measure at fixed positions, the single sensor system can continuously scan through different wavelengths to detect liquid levels and pH values without interruption, providing continuous monitoring capability.

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 continuous and accurate measurement of liquid levels and pH in cell culture solutions, reducing the impact of environmental factors like air flow and allowing for rapid determination of solution amounts dispensed, while maintaining a compact and cost-effective apparatus.

Implementation Method 1

measuring a first absorbance of the cell culture solution with respect to the first light beam, and a second absorbance of the cell culture solution with respect to the second light beam

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentUS9470572B2Method and apparatus for measuring liquid level of cell culture solution

Publication Date: 2016.10.18 NIHON KOHDEN CORP

AI summary

A method of measuring a liquid level of a cell culture solution stored in a cell vessel, includes: irradiating the cell culture solution with at least two kinds of light beams including a first light beam having a first wavelength and a second light beam having a second wavelength; measuring a first absorbance of the cell culture solution with respect to the first light beam, and a second absorbance of the cell culture solution with respect to the second light beam; and determining a liquid level of the cell culture solution based on the first absorbance and the second absorbance.