Optical Light Curtain for Liquid Dispense Verification
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Solution Overview
Problem
Existing systems for verifying the successful dispensing of liquids, such as pipettes, face challenges in accurately detecting droplet dispensing due to high costs, space consumption, and reliability issues, especially with smaller sample sizes, as current pressure transducers cannot distinguish between a droplet clinging to the pipette tip and one that has been dispensed.
Innovation Solution
A system utilizing a light curtain created by light emitters and detectors positioned horizontally relative to the dispensing plane, where the liquid dispense device is above the light curtain, generating a signal when the liquid interrupts the light path upon successful dispensing onto a target plate, ensuring accurate verification without gaps for droplets of at least three microliters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure monitoring systems are used to detect dispense, then pressure changes during dispense can be detected, but existing pressure transducers cannot distinguish between a droplet clinging to the tip and a dispensed droplet
Solution Approach 1:
The patent replaces the mechanical pressure monitoring system with an optical detection system. A light source emits light through a light path, and a photodetector detects interruptions in this light path. When a droplet is dispensed and interrupts the light path, the photodetector generates a signal confirming successful dispense. This optical system eliminates the inability of pressure transducers to distinguish between clinging and dispensed droplets.
Solution Approach 2:
The patent introduces an optical intermediary (light path with photodetector) between the dispense mechanism and the detection system. The light curtain acts as an intermediary medium that the dispensed droplet must interrupt to be detected, providing a clear distinction between clinging droplets (which don't interrupt the light) and dispensed droplets (which do interrupt the light).
2Measurement precision
If vision systems with cameras are used to capture droplets, then droplet detection is possible, but complex image processing and analysis are required
Solution Approach 1:
The patent extracts only the essential detection function from complex vision systems. Instead of using cameras and image processing algorithms, it uses a simple photodetector to detect light path interruptions. This extracts the core detection capability while eliminating unnecessary complexity in imaging and processing.
Solution Approach 2:
The patent substitutes the mechanical/optical complex system (camera + image processing) with a simpler optical detection system (light source + photodetector). The photodetector directly converts light interruption into an electrical signal, eliminating the need for complex image capture, processing, and analysis.
3Reliability
If existing verification techniques are used, then dispense detection is attempted, but they consume great deal of physical space and are expensive
Solution Approach 1:
The patent extracts the essential verification function from bulky existing systems. By using a focused light path with emitters and detectors positioned close to the dispense tip, it achieves reliable verification in a compact form factor, eliminating the need for large physical spaces required by conventional systems.
4Quantity of substance
If existing techniques are used for small sample sizes, then detection is attempted, but reliability and accuracy become more pronounced challenges
Solution Approach 1:
The patent applies local quality by concentrating the optical detection field precisely where the droplet is dispensed. The light path is focused through the dispense region, and the photodetector is positioned to detect interruptions at the exact location of droplet release. This localized detection approach maintains high precision even for very small droplet volumes.
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 solution provides reliable and accurate positive dispense verification, reducing false positives and negatives, is cost-effective, and adaptable for use in various spaces, ensuring precise detection of even smaller droplet volumes.
Implementation Method 1
Each of the plurality of detectors is coupled to an amplifier. The amplifier generates a signal in response to an interrupt in the transmission of light from the light emitters to the light detectors when the light path is disrupted by the dispense of liquid
Data Source
AI summary
Systems and methods for positive dispense verification. In one aspect, a system has a plurality of light emitters. The light from the emitters is directed toward a plurality of light detectors across a proximately horizontal plane. The liquid dispense device is positioned above the horizontal plane of light emission from the plurality of light emitters to the plurality of light detectors such that the dispensed liquid will travel through the horizontal plane defined by the emitted light and onto the container being inoculated. Each of the plurality of detectors is coupled to an amplifier. The amplifier generates a signal in response to an interrupt in the transmission of light from the light emitters to the light detectors when the light path is disrupted by the dispense of liquid confirming the liquid was dispensed onto the container.