Optically Black AM-EWOD Array Structure for Fluorescence Detection
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Solution Overview
Problem
Conventional Active Matrix Electrowetting-On-Dielectric (AM-EWOD) devices face challenges in optical detection of fluorescence, particularly for single cell detection and counting, due to background fluorescence from planarization layers and reflective electrodes causing optical cross-talk.
Innovation Solution
An optically black array element structure is implemented in the AM-EWOD device, featuring a blackened planarization layer between the TFT device and the hydrophobic coating, which reduces background interference and enhances fluorescence detection by using an optically black material, such as graphite or carbon black, to minimize reflections and background patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional planarization layers and reflective electrodes are used in AM-EWOD devices, then the device structure is simple and manufacturing is easier, but background fluorescence and optical cross-talk occur which reduce detection precision
Solution Approach 1:
The patent extracts and removes the problematic planarization layer from the device structure. By eliminating this layer that causes background fluorescence, the invention achieves improved fluorescence detection precision without requiring complex compensatory structures, thus resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The patent converts the harmful reflective property of electrodes into a beneficial feature by using the electrode reflection to enhance the fluorescence signal from droplets. This approach transforms optical cross-talk from a detrimental effect into a signal enhancement mechanism, improving detection precision while maintaining structural simplicity.
2Measurement precision
If reflective electrodes are used to enhance droplet visibility, then droplet detection is improved, but optical cross-talk increases which compromises imaging ability
Solution Approach 1:
The patent applies different optical properties to different spatial locations within the device. The electrodes are designed to be reflective specifically in the regions where droplet detection is needed, while other areas maintain different properties. This localized optimization allows droplet detection enhancement without generating excessive optical cross-talk that would compromise overall imaging ability.
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
The optically black array element structure improves fluorescence detection and cell counting accuracy by eliminating background fluorescence and reflections, enabling precise detection of single cells within liquid droplets.
Implementation Method 1
an optically black material, such as graphite or carbon black, to minimize reflections and background patterns
Implementation Method 2
Electrowetting on dielectric (EWOD) is a well-known technique for manipulating droplets of fluid by application of an electric field
Data Source
AI summary
An active matrix electro-wetting on dielectric (AM-EWOD) device has an optically black array element structure to enhance optical detection of constituents within a liquid droplet. The AM-EWOD device includes a thin film transistor (TFT) substrate assembly having a hydrophobic layer; thin film electronics having a plurality of array elements arranged in an array of rows and columns, each of the array elements including an array element electrode and a TFT device; and an optically black material disposed between a plane of the TFT device and the hydrophobic layer. The TFT substrate assembly further includes a planarization structure that includes a component having the optically black material. The planarization structure has a planarization component disposed between the TFT device and the array element electrode, and an ionic barrier disposed between the array element electrode and the hydrophobic coating. The planarization component or the ionic barrier includes the optically black material.