Sensor Package with Exposed Sensitive Surface
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Solution Overview
Problem
Existing sensor packages are completely sealed, preventing direct contact between the sensor and its environment, which is undesirable in certain applications where environmental interaction is necessary.
Innovation Solution
A package design that uses a duroplast encapsulation material to cover the sensor attachment area and electrical connections while leaving the sensitive surface exposed, with optional additional shielding materials to minimize stress and ensure thermal expansion matching, allowing direct environmental contact while protecting other package elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a completely sealed package is used to protect the sensor, then the sensor is protected from environmental damage, but direct contact between the sensor and environment is prevented
Solution Approach 1:
The package is segmented into two distinct regions: a sealed encapsulation region covering the carrier element and attachment material, and an exposed region leaving the sensitive surface accessible to the environment. This segmentation allows simultaneous protection of vulnerable components and environmental contact capability.
Solution Approach 2:
Different parts of the sensor assembly have different protection requirements. The encapsulation material provides protection to the carrier element and attachment material where needed, while deliberately leaving the sensitive surface exposed. This local differentiation of protection quality resolves the contradiction between overall protection and localized environmental contact.
2Adaptability or versatility
If the sensitive surface is exposed to the environment, then direct contact is enabled, but the sensor becomes vulnerable to environmental damage
Solution Approach 1:
The package structure segments the protection coverage, applying encapsulation material to specific areas (carrier element and attachment material) while leaving the sensitive surface exposed. This selective segmentation enables environmental contact where needed while maintaining protection where vulnerable.
Solution Approach 2:
The encapsulation provides localized protection quality - fully protecting the carrier element and attachment material from environmental factors, while intentionally providing no protection to the sensitive surface to enable environmental interaction. This local quality differentiation resolves the contradiction.
3Reliability
If encapsulation material covers the entire sensor assembly, then comprehensive protection is achieved, but stress is induced on the sensor assembly
Solution Approach 1:
The encapsulation coverage is segmented to exclude the sensor assembly from the encapsulated region. By limiting the encapsulation material's contact area to only the carrier element and attachment material, stress induction on the sensor assembly is eliminated while protection of other components is maintained.
Solution Approach 2:
The encapsulation material provides protection locally to the carrier element and attachment material, but deliberately avoids contacting the sensor assembly to prevent stress induction. This local quality control resolves the contradiction between comprehensive protection and stress prevention.
4Adaptability or versatility
If different materials with different thermal expansion coefficients are used in the package, then functional requirements are met, but stress is induced during temperature changes
Solution Approach 1:
The package structure segments the thermal expansion stress paths by separating the sensor assembly from the encapsulation material through non-contact design. This segmentation prevents direct stress transmission between materials with different thermal expansion coefficients, allowing flexible material selection without thermal stress penalties.
Solution Approach 2:
The encapsulation material's thermal properties are locally relevant only to the carrier element and attachment material it contacts, not to the sensor assembly. This local quality separation allows independent material optimization for each component without thermal stress coupling, resolving the contradiction between material flexibility and thermal stress.
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 design provides a robust and reliable sensor package that maintains sensitivity and operational integrity by isolating the sensitive surface from harsh environments while enabling direct contact, reducing stress-induced errors and enhancing electromagnetic compatibility.
Implementation Method 1
an encapsulation of a first material, in which the encapsulation covers the sensor attachment area of the carrier element and the sensor attach material and leaves the at least one sensitive surface free from the first material
Implementation Method 2
a sensor attach material for attaching the sensor assembly to the sensor attachment area of the carrier element
Implementation Method 3
the external (harsh) environment can only reach the sensitive surface of the sensor assembly (and possibly some area surrounding it), and the package material itself, but not any other elements in the package
Implementation Method 4
In order to more accurately match thermal expansion coefficients of elements inside the package (especially between the sensor assembly and the carrier element)
Data Source
AI summary
Package (1) having a sensor assembly (2) with at least one sensitive surface (21) and an attachment surface (22), a carrier element (3) with a sensor attachment area (31), and a sensor attach material (4) for attaching the sensor assembly (2) to the sensor attachment area (31) of the carrier element. The package (1) comprises an encapsulation (5) of a first material, in which the encapsulation (5) covers the sensor attachment area (31) of the carrier element (3) and the sensor attach material (4) and leaves the at least one sensitive surface (21) free from the first material.