Pyroelectric Sensor with Floating Gate for Biosensing
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Solution Overview
Problem
Conventional biosensing technologies face challenges in achieving high sensitivity and accuracy in detecting temperature changes due to limitations in thermistor sensitivity and environmental temperature fluctuations, particularly in calorimetric sensors, which often require precise temperature resolution and are cumbersome for real-time, high-resolution detection.
Innovation Solution
A pyroelectric device with a two-dimensional conductive channel and a floating gate is used, where the floating gate is functionalized to detect specific species, causing heat flow to a pyroelectric layer, generating an electrical signal based on the presence and amount of the species, with a dielectric layer and controlled photon source for enhanced sensitivity and thermal isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional calorimetric sensors are used to detect temperature changes, then chemical and biological species can be detected, but the temperature resolution is insufficient and environmental temperature fluctuations interfere with detection accuracy
Solution Approach 1:
The sensor is divided into two symmetrical halves, each with its own pyroelectric layer and detection channel. One half detects the target temperature change while the other serves as a reference to compensate for environmental fluctuations, enabling differential measurement that rejects common-mode noise
Solution Approach 2:
The patent employs pyroelectric materials with high pyroelectric coefficients to amplify the electrical signal generated by temperature changes. By selecting materials with optimized pyroelectric properties and adjusting operational parameters, the sensor achieves enhanced temperature resolution and sensitivity
2Measurement precision
If pyroelectric layers are used to improve temperature change sensitivity, then detection accuracy improves, but the device becomes more complex and requires precise thermal isolation
Solution Approach 1:
The patent extracts and isolates the pyroelectric detection elements from the bulk substrate by creating suspended or thermally isolated structures. This separation allows the pyroelectric layers to respond primarily to target temperature changes while minimizing coupling to environmental thermal noise, reducing the need for complex external thermal isolation
Solution Approach 2:
The sensor design introduces controlled asymmetry in the thermal pathways: one side is designed with high thermal conductivity to the target source while the other side maintains low thermal conductivity to the environment. This asymmetric thermal design enhances the differential response to target temperature changes while simplifying the overall thermal isolation requirements
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 significantly improves temperature change sensitivity, allowing for precise detection of chemical and biological species with high resolution and accuracy, overcoming limitations of conventional calorimetric sensors by amplifying temperature changes and reducing environmental noise.
Implementation Method 1
a pyroelectric layer... configured such that the detection of which gives rise to heat flow to or from the thermally proximal pyroelectric layer to allow the pyroelectric layer to generate an electrical signal
Implementation Method 2
the pyroelectric layer is capacitively configured with respect to each of the two dimensional conductive channel and the floating gate... wherein a dielectric layer is located between the two dimensional conductive channel and the second portion of the floating gate
Data Source
Figure 1a~1b
Figure 2
Figure 3~4
AI summary
An apparatus comprising a pyroelectric layer, a two dimensional conductive channel and a floating gate. The pyroelectric layer is capacitively configured with respect to each of the two dimensional conductive channel and the floating gate. The floating gate comprises electrically connected first and second portions, the first portion is in thermal proximity to the first portion of the pyroelectric layer. The second portion is configured to overlie and gate flow of electrical charge through the two dimensional conductive channel by charge in the second portion of the floating gate. The first portion is functionalised to detect one or more proximal specific species. Such detection gives rise to heat flow to or from the thermally proximal pyroelectric layer to allow the pyroelectric layer to generate an electrical signal dependent upon one or more of the presence and amount of the specific detected species.