Micro Heater Array for EWOD Droplet Temperature Control
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Solution Overview
Problem
Conventional heating devices in microfluidic apparatuses are inadequate for independent heating of pixels and thermal sensing, failing to maintain precise temperature control for droplets, especially in EWOD-based systems.
Innovation Solution
A heating device comprising an array of micro heaters arranged in rows and columns, with each micro heater having a resistive heating element, conductive lines, and a substrate, allowing for precise temperature control and thermal sensing by integrating micro heaters and thermal sensors with electrowetting on dielectric devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional heater is used to raise the temperature in the microfluidic apparatus, then the general temperature increases, but the droplets in different areas (pixels) cannot have different temperatures
Solution Approach 1:
The heating device is divided into multiple independent micro-heaters arranged in an array corresponding to different pixels. Each micro-heater can be independently controlled to provide localized heating to droplets in specific areas, enabling precise temperature control for each pixel without requiring a single complex heating system.
Solution Approach 2:
Different regions of the microfluidic apparatus can have different heating characteristics through the array of micro-heaters. Each micro-heater is designed to provide appropriate heating for its corresponding pixel, allowing different droplets in different areas to maintain different temperatures as needed by the application.
2Measurement precision
If macroscale thermal sensors are used for temperature sensing, then the sensing capability is limited, but they are insufficient for precise pixel-based temperature measurement
Solution Approach 1:
The thermal sensing function is segmented into multiple micro-scale thermal sensors that correspond to each pixel in the array. This segmentation enables independent temperature measurement for each pixel, providing the precision needed for localized thermal management while maintaining a structured array layout that matches the heating configuration.
Solution Approach 2:
Each pixel position is equipped with its own micro-thermal sensor that provides localized temperature measurement capability. This allows different areas of the device to have specialized sensing for their specific thermal requirements, enabling precise temperature monitoring and control for each droplet location.
3Adaptability or versatility
If individual heating control for each pixel is implemented, then precise temperature control is achieved, but the device complexity increases
Solution Approach 1:
Both heating and sensing functions are segmented into corresponding micro-elements arranged in the same array pattern. This segmentation approach allows independent control of each pixel's thermal characteristics while maintaining a regular, scalable structure that facilitates manufacturing and integration.
Solution Approach 2:
The micro-heaters and micro-thermal sensors are designed with universal characteristics that allow them to serve multiple functions. The array structure and individual element design enable the system to handle various thermal management scenarios including heating, cooling, and temperature maintenance for different droplets simultaneously.
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 independent and precise heating of micro objects, such as droplets, with defined temperature zones, improving thermal management and reducing power consumption by maintaining consistent temperatures during operation.
Implementation Method 1
each of the micro heaters comprises a heating element, a first conductive line and a second conductive line... the heating element is a resistive heating element
Implementation Method 2
The microfluidic apparatus may utilize an electrowetting on dielectric (EWOD) technique. That is, when a droplet of fluid is present on or above one of the electrodes of the apparatus and an electrical potential is applied to that electrode, the contact angle on the interface between the droplet and the electrode is changed, thereby generating a lateral pushing force to cause the droplet to move on the electrode.
Data Source
AI summary
There is provided a heating device to independently and/or effectively heat the micro objects manipulated by a micro apparatus/system, for example the droplets of fluids in an electrowetting on dielectric EWOD device of a microfluidic apparatus. The heating device may include a plurality of micro heaters arranged in an array of rows and columns, and the micro heaters of the heating device may be disposed in relative to the electrode elements of the EWOD device, respectively. Therefore, the micro heaters of the heating device may heat one of the electrode elements of the EWOD device, thereby preventing thermal effect of the micro object on the other electrode elements.