Dual Sensor Assembly Overmolding Alignment Tool

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Solution Overview

Problem

Existing sensor assemblies face challenges in achieving accurate placement and secure retention of redundant sensors during the overmolding process, leading to potential delamination and reduced reliability, especially in harsh environments, due to the use of separate supports which increase complexity and cost.

Innovation Solution

A method for forming a dual sensor assembly using an alignment tool with notch regions to securely hold sensor packages during overmolding, eliminating the need for a carrier structure, ensuring the sensing axes are laterally displaced and parallel, and overmolding the sensor packages directly with the overmold material.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate support is used to retain the sensor package during overmolding, then the sensor package can be securely held in position, but the complexity and cost of the sensor assembly increases

Engineering Contradiction:
Improvesecure retention of sensor packageVSAvoidcomplexity of sensor assembly
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the separate support structure from the sensor assembly by directly integrating the sensor package into the mold cavity. The sensor package is retained during overmolding through direct contact with the mold cavity walls and positioning features formed integrally with the mold, eliminating the need for additional support components.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent combines the functions of the support structure and the mold cavity into a single integrated system. The mold cavity itself provides both the shaping function and the retention function during overmolding, merging what were previously separate components into one unified structure.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If a separate support is used to retain the sensor package during overmolding, then the sensor package can be securely held in position, but the cost of the sensor assembly increases

Engineering Contradiction:
Improvesecure retention of sensor packageVSAvoidcost of sensor assembly
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent eliminates the separate support component and its associated manufacturing, assembly, and quality control costs by using the mold cavity itself to provide retention during overmolding.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The mold cavity performs multiple functions: it shapes the overmold material, positions the sensor package, and provides retention during the overmolding process. This multi-functionality eliminates the need for dedicated support structures.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Manufacturing precision

If a separate support is used to retain the sensor package during overmolding, then the sensor package can be held in position, but delamination can occur between the support and overmold material

Engineering Contradiction:
Improvepositioning of sensor packageVSAvoidbonding between support and overmold material
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

By removing the separate support structure, the patent eliminates the interface between the support and overmold material that is prone to delamination. The sensor package is directly surrounded by overmold material without an intermediate support layer.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the positioning and retention functions into the mold cavity itself, creating a direct bond between the sensor package and overmold material without an intermediate support layer that could delaminate.

Inventive Principle:
Principle #5Merging (Combining)

4Measurement precision

If redundant sensors are placed in the same sensing axis, then accurate placement is required, but secure retention during overmolding becomes particularly difficult

Engineering Contradiction:
Improveaccurate placement of sensorsVSAvoidsecure retention during overmolding
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent removes the need for complex support structures that would be required to hold multiple redundant sensors during overmolding. The mold cavity itself provides the retention mechanism, simplifying the process for multiple sensors.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The sensor packages are pre-positioned in the mold cavity with precise alignment features before the overmolding process begins. This preliminary positioning ensures accurate placement of redundant sensors while the mold cavity provides secure retention during overmolding.

Inventive Principle:
Principle #10Preliminary action

5Reliability

If a separate support is used to retain the sensor package during overmolding, then the sensor package can be held in position, but the alignment of sensing axes may not be accurate

Engineering Contradiction:
Improveretention of sensor packageVSAvoidalignment of sensing axes
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

By eliminating the separate support structure, the patent removes the potential misalignment interface between the support and sensor package. The sensor packages are directly positioned by the mold cavity itself, improving alignment accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The mold cavity includes integral positioning features and alignment mechanisms that ensure accurate alignment of sensing axes before the overmolding process begins. This preliminary alignment is maintained throughout the overmolding process.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3756851B1Dual sensor assembly and method of fabrication
Publication Date: 2022.02.09 NXP BV
  • EP3756851B1 patent drawingFigure 1~3
  • EP3756851B1 patent drawingFigure 4~6
  • EP3756851B1 patent drawingFigure 7~8

AI summary

A sensor assembly includes first and second sensor packages adjacent to one another and directly overmolded with an overmold material without being attached to a carrier structure. The first sensor package includes a first sensor die, a first set of connector pins electrically connected to the first sensor die, a first housing in which the first sensor die is located, the first housing having first and second surfaces spaced apart from one, and a first component positioned in proximity to the second surface of the first housing. The second sensor package includes a second sensor die, a second set of connector pins electrically connected to the second sensor die, a second housing in which the second sensor die is located, the second housing having third and fourth surfaces spaced apart from one another, and a second component positioned in proximity to the fourth surface of the second housing.