Flexible HDI Circuit Board Arrangement for Tolerance Compensation

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Solution Overview

Problem

Existing motor vehicle control device arrangements face challenges in achieving a robust, compact, and cost-effective design with flexible tolerance compensation for connecting peripheral components, as they are either expensive to manufacture or limit integration and mobility.

Innovation Solution

A printed circuit board arrangement using a flexible, epoxy resin-based standard printed circuit board with a recess and an overlapping HDI printed circuit board, allowing for mechanical and electrical connections, and enabling tolerance compensation while maintaining a compact and integrated design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a rigid ceramic substrate is used for control electronics, then manufacturing precision and robustness are improved, but device complexity and manufacturing cost increase

Engineering Contradiction:

Improvetolerance compensationVSAvoidconstruction complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The circuit board is divided into a rigid carrier board and a flexible HDI board that can move independently. The rigid carrier provides stable mounting, while the flexible HDI board absorbs tolerance variations through its ability to bend and deform, eliminating the need for complex tolerance compensation mechanisms.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The flexible HDI board changes its physical parameters (shape, position) in response to tolerance variations. By allowing the HDI board to deform within certain limits, the system adapts to manufacturing tolerances without requiring precise control, thereby simplifying the overall construction.

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If a rigid printed circuit board is used, then structural stability is improved, but flexibility and tolerance compensation capability deteriorate

Engineering Contradiction:

Improvestructural stabilityVSAvoidflexibility

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The circuit board system is segmented into a rigid carrier board that provides structural stability and a flexible HDI board that provides adaptability. This segmentation allows each part to fulfill its primary function without compromise.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system uses a composite structure combining rigid and flexible materials. The rigid carrier board (typically FR4 or similar) provides mechanical strength, while the flexible HDI board (with flexible substrate material) provides bending capability, creating a composite system that exhibits both stability and flexibility.

Inventive Principle:

Principle #40Composite materials

3Manufacturing precision

If ceramic carrier material is used, then manufacturing precision is improved, but manufacturing cost increases

Engineering Contradiction:

Improvetolerance controlVSAvoidmanufacturing cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

Instead of using expensive ceramic substrates, the invention employs inexpensive flexible HDI boards that can accommodate tolerance variations through deformation. This approach eliminates the need for costly ceramic materials while maintaining manufacturing precision through the flexible connection mechanism.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The flexible HDI board uses parameter changes (deformation, bending) to compensate for tolerance variations, replacing the need for precision-critical ceramic substrates. This allows the use of cheaper materials while maintaining the required functional precision.

Inventive Principle:

Principle #35Parameter changes

4Extent of automation

If highly integrated electronics are implemented, then device functionality is improved, but device size increases

Engineering Contradiction:

Improveintegration levelVSAvoidcontrol unit size

Core Design Contradiction:

Extent of automationVSVolume of moving object

Solution Approach 1:

The flexible HDI board allows for three-dimensional routing and stacking of conductors, enabling high integration density without increasing the planar footprint. Signals can travel through multiple layers and bend at various angles, packing more functionality into a smaller space.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The flexible HDI board structure allows for nested routing where conductors are arranged in multiple layers, with inner layers nested within outer layers. This nesting approach increases integration density while minimizing the overall device volume.

Inventive Principle:

Principle #7Nested doll (Nesting)

Data Source

PatentEP2671431B1Circuit board arrangement

Publication Date: 2017.07.12 ZF FRIEDRICHSHAFEN AG

Figure 1~3
Figure 4a~4b

AI summary

The invention relates to a circuit board arrangement (1) for a control device (2) of a motor vehicle, wherein the circuit board arrangement (1) has a standard circuit board (4) which is in particular flexible, in particular a FR4 circuit board, wherein in the standard circuit board (4) a cutout (5) is formed, in particular in the form of a through opening, and wherein the circuit board arrangement (1) also has a HDI circuit board (7) which is disposed on the standard circuit board (4) overlapping the cutout (5).