Monolithic Refractory Micro-Hotplate for Fast Pulsed IR Emission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing MEMS infrared emitters are limited by low operating frequencies and high power consumption, with complex fabrication and compromised IR emission characteristics due to material constraints.
Innovation Solution
A radiator device using a single conductive refractory material with a suspended plate and support arms, capable of operating at high temperatures without degrading, allowing for reduced size, increased frequency, and enhanced IR emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional MEMS hotplates use resistive layers on insulators or suspended membranes with multiple layers, then IR emission can be achieved, but the fabrication becomes complex and operating frequency is limited to about 100 Hz
Solution Approach 1:
The patent combines the heater and radiator functions into a single monolithic refractory ceramic component, eliminating the need for separate resistive layers, insulating layers, and support structures. This integration simplifies fabrication to a single piece construction while enabling higher operating frequencies above 100 Hz by reducing thermal mass and structural complexity.
Solution Approach 2:
The refractory ceramic plate serves multiple functions simultaneously: it acts as the resistive heater, the radiating surface, and the structural support element. This multi-functionality eliminates the need for separate components, simplifying fabrication while improving thermal response time for high-frequency operation.
2Use of energy by moving object
If conventional MEMS hotplates use multiple material layers (resistive layer, insulating layers, support structures), then structural integrity is maintained, but power consumption increases and IR emission characteristics are compromised
Solution Approach 1:
By merging the heater and radiator into a single refractory ceramic component, the patent eliminates thermal interfaces and heat loss pathways present in multi-layer structures. This reduces power consumption while improving IR emission efficiency, as heat is directly converted to radiation without being trapped in insulating layers or conducted away through support structures.
Solution Approach 2:
The patent changes the material parameter from conventional low-temperature materials to high-temperature refractory ceramic, enabling operation at temperatures above 1000 K. This parameter change improves the infrared emission characteristics by increasing the intensity and bandwidth of radiation while reducing the power required to achieve these temperatures.
3Temperature
If conventional MEMS hotplates operate at temperatures above 1000 K, then IR emission intensity increases, but material degradation occurs limiting practical operation
Solution Approach 1:
The patent changes the material composition parameter to use refractory ceramic with high melting point and thermal stability. This enables reliable operation at temperatures above 1000 K, as the refractory material resists degradation, oxidation, and structural failure that limit conventional materials. The material parameter change directly enables higher operating temperatures while maintaining reliability.
4Productivity
If conventional MEMS hotplates use suspended membrane structures with multiple layers, then thermal isolation is achieved, but device size increases and frequency response is limited
Solution Approach 1:
By combining the heater and radiator into a single compact refractory ceramic plate, the patent eliminates the need for extended support structures and multiple layers required for thermal isolation in conventional designs. This monolithic structure achieves thermal isolation through material properties rather than geometric complexity, reducing device size while improving frequency response above 100 Hz.
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 device achieves higher operating frequencies and reduced power consumption while maintaining intense IR emission, with the potential to emit visible light, surpassing conventional halogen lamps in intensity and bandwidth.
Implementation Method 1
The support arms 4 are heater springs which are resistively heated to warm the plate 2
Implementation Method 2
capable of emitting broadband infrared radiation at temperatures of over 2000 K
Data Source
Figure 1~2
Figure 3~5
Figure 6~8
AI summary
An IR radiator element (1) suitable for use as a miniature infrared emitter (micro-hotplate) in a gas sensor, IR-spectrometer or electron microscope. The micro-hotplate comprises a plate (2) supported by multiple support arms (4). The plate and arms are fabricated as a MEMS device comprising a single contiguous piece of electrically-conducting refractory ceramic such as hafnium carbide (HfC) or tantalum hafnium carbide (TaHfC). Each of the arms (4), in addition to providing structural cantilever support for the plate (2), acts as a heating element for the plate (2). The plate (2) is heated by applying a voltage across the arms (4). The arms (4) may also be shaped to absorb thermomechanical stress which arises during the heating and cooling of the arms and plate. The plate, which may have an area of less than 0.05 mm2 and a thickness of between 1% and 10% of the largest dimension of the plate (2), for example, can be heated to 4,000 K or more and cooled again with a duty cycle of as little 0.5 ms, thereby permitting pulsed operation at frequencies of up to 2 kHz. Its small size (10 - 200 μm) and low power consumption (e.g. 10 - 100 mW) make the micro-hotplate suitable for use in cryogenic applications, in miniaturized devices or in battery-powered devices such as mobile phones.