AM-EWOD Column Detection Circuit for Compact Sensing
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Solution Overview
Problem
Existing AM-EWOD devices face a challenge in balancing integrated sensing capabilities with the desire for small array element size, as integrated sensing circuitry requires additional components that increase the size of the array element circuitry and limit miniaturization.
Innovation Solution
The integration of a column detection circuit within the thin film electronics substrate, which performs sensing functions without adding components to the array element circuitry, allowing for capacitance measurement through addressing lines used for control signals, enabling sensing without enlarging the array element size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If integrated sensing circuitry is added to each array element, then sensing capability is improved, but array element size increases
Solution Approach 1:
The sensing function is extracted from individual array elements and consolidated into shared column detection circuits. Each column detection circuit serves multiple array elements, eliminating the need for dedicated sensing components in each element while maintaining sensing capability across the entire array.
Solution Approach 2:
The column addressing lines are designed to serve dual purposes: controlling the array elements during actuation and sensing capacitance values during measurement. This multi-functionality eliminates the need for separate sensing circuitry in each array element, reducing overall complexity and size.
2Measurement precision
If additional sensing components are integrated into array element circuitry, then sensing function is enhanced, but device complexity increases
Solution Approach 1:
The control and sensing functions are merged into a single integrated system. The column detection circuits perform both actuation control and capacitance sensing, eliminating the need for separate sensing circuitry and reducing overall device complexity.
Solution Approach 2:
The addressing lines and detection circuits are designed to perform multiple functions: they control array elements during actuation and measure capacitance values during sensing operations. This multi-functionality reduces the total number of components and simplifies the overall device architecture.
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 configuration achieves effective sensing with a high signal-to-noise ratio and closed-loop operation without increasing the size of the array element circuitry, facilitating high-resolution droplet manipulations and maintaining a compact device design.
Implementation Method 1
a column detection circuit comprising an addressing circuit that applies an electrical perturbation during a sensing operation to the column addressing line of an array element being sensed, and a measuring circuit that measures an output signal from one of the column addressing lines, wherein the output signal varies based upon a capacitance present at the element electrode
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 AM-EWOD device includes a plurality of array elements arranged in an array of rows and columns; each column including a column addressing line that applies control signals to a corresponding column of array elements, and each row including a row addressing line that applies control signals to a corresponding row of array elements; each array element including an element electrode for receiving an actuation voltage and a switch transistor, wherein the switch transistor is electrically connected between the column addressing line and the element electrode and is switched by the row addressing line; and a column detection circuit comprising an addressing circuit that applies an electrical perturbation during a sensing operation to the column addressing line of an array element being sensed, and a measuring circuit that measures an output signal from one of the column addressing lines, wherein the output signal varies based upon a capacitance present at the element electrode.