MEMS IR Emitter Package with LCP Wall and Filter Lid
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current photoacoustic sensor emitter packages are costly, bulky, and unreliable due to high tooling costs, material expenses, and potential infrared signal leakage, making them unsuitable for widespread adoption in gas sensing applications.
Innovation Solution
A compact emitter package featuring a MEMS infrared radiation source surrounded by a rigid Liquid Crystal Polymer (LCP) wall structure and a lid with an integrated filter structure that filters broadband infrared radiation to a specific wavelength range, reducing package size and tooling costs while preventing signal leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ceramic packages with deep cavity are used, then reliability and rigid architecture are improved, but tooling costs increase too much
Solution Approach 1:
The patent changes the material parameter from ceramic to plastic, and the cavity depth parameter from deep (1mm minimum) to shallow (0.2-0.5mm), thereby reducing tooling costs while maintaining package reliability through alternative design features
Solution Approach 2:
The patent replaces expensive ceramic materials with cheaper plastic materials for the package structure, achieving cost reduction while maintaining functional performance through the use of standard plastic molding processes
2Strength
If metal can packages are used, then package strength is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive metal can materials with cheaper plastic materials, achieving cost reduction while maintaining structural integrity through optimized plastic molding and reinforcement features
Solution Approach 2:
The patent changes the material parameter from metal to plastic, and optimizes the cavity depth parameter to 0.2-0.5mm, thereby reducing manufacturing costs while maintaining package strength through alternative structural design
3Ease of manufacture
If molded QFN packages are used, then cost is reduced, but reliability deteriorates due to cracking at leadframe interface
Solution Approach 1:
The patent extracts the problematic leadframe component from the package design, using wire bonds directly attached to the substrate, thereby eliminating the cracking issue at the leadframe-mold compound interface while maintaining cost-effectiveness
Solution Approach 2:
The patent inverts the conventional approach by attaching wire bonds to the substrate rather than using a leadframe structure, thereby eliminating the reliability issue while maintaining the cost benefits of molded packages
4Ease of manufacture
If wire bonding space is provided, then wire bonding is enabled, but package footprint increases
Solution Approach 1:
The patent moves the wire bonding operation to a different spatial arrangement by attaching wires to the substrate surface rather than requiring lateral space, thereby enabling wire bonding without increasing package footprint
Solution Approach 2:
The patent performs wire bonding before molding the package cavity, thereby eliminating the need for additional space during the bonding process and reducing the overall package footprint
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 solution provides a cost-effective, reliable, and miniaturized photoacoustic sensor emitter package that effectively filters infrared radiation, enabling efficient gas detection with reduced manufacturing costs and improved reliability, suitable for applications like CO2 sensing in smart home and IoT devices.
Implementation Method 1
The lid structure may comprise a filter structure for filtering the infrared radiation emitted from the MEMS infrared radiation source thereby providing a filtered infrared radiation in a reduced second wavelength range
Implementation Method 2
The photo acoustic (PA) effect is based on the transformation of pulsed radiation energy into sound. Pulsed radiation (e.g., infrared: IR) may be emitted into a measurement chamber comprising a gas or a mixture of gases containing at least one analyte
Implementation Method 3
The gas may absorb the energy of the emitted pulsed radiation which causes an alternating local heating of the gas, which leads to a thermal expansion inside the measurement chamber creating a pressure wave
Data Source
AI summary
The present disclosure concerns an emitter package for a photoacoustic sensor, the emitter package comprising a MEMS infrared radiation source for emitting pulsed infrared radiation in a first wavelength range. The MEMS infrared radiation source may be arranged on a substrate. The emitter package may further comprise a rigid wall structure being arranged on the substrate and laterally surrounding a periphery of the MEMS infrared radiation source. The emitter package may further comprise a lid structure being attached to the rigid wall structure, the lid structure comprising a filter structure for filtering the infrared radiation emitted from the MEMS infrared radiation source and for providing a filtered infrared radiation in a reduced second wavelength range.