PCB Scale Coding via Joule Heating for Mass Production

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Solution Overview

Problem

Existing measurement systems for recording absolute values of angles or distances are expensive due to the need for individual coding on each scale, particularly in optical systems, and require complex manufacturing techniques.

Innovation Solution

A scale with a coding system featuring electrodes and an insulating substrate where the conductive connection is irreversibly destroyed by applying an electric current, allowing for mass production and flexible encoding of multiple scales using mature technologies like printed circuit boards, with segmented coding elements for improved accuracy and parasitic capacitance reduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If individual coding is applied to each scale in optical measurement systems, then scale identification accuracy is improved, but manufacturing time and cost increase significantly

Engineering Contradiction:
Improvescale identification accuracyVSAvoidmanufacturing speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent replaces optical coding systems with electrical coding systems. Instead of using optical patterns that require complex optical sensors and individual application, the invention uses electrical conductive tracks on PCBs that can be coded through simple electrical connections. This substitution enables automated, high-speed coding during PCB manufacturing without requiring subsequent individual optical coding operations, thus resolving the contradiction between identification accuracy and manufacturing productivity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the coding parameter from optical properties (reflectivity, absorption) to electrical properties (conductive vs. non-conductive tracks). This parameter change allows the coding to be integrated into the PCB manufacturing process itself, where conductive tracks are naturally created through standard PCB fabrication techniques. The electrical parameters can be precisely controlled and read automatically, maintaining identification accuracy while enabling mass production speeds.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If complex manufacturing techniques are used for coding scales, then coding precision is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improvecoding precisionVSAvoidmanufacturing process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent makes the PCB serve multiple functions: it provides the structural base for the scale, creates the conductive tracks for measurement signals, and simultaneously provides the coding information through its own trace patterns. This multi-functionality eliminates the need for separate coding components or complex coding processes, as the existing PCB manufacturing infrastructure is used for both measurement and identification purposes, thereby reducing device complexity while maintaining coding precision.

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

Solution Approach 2:

The PCB manufacturing process itself provides the coding without requiring additional specialized equipment or processes. The conductive tracks that are naturally created during standard PCB fabrication serve dual purposes: electrical connectivity for measurement and spatial patterns for identification. This self-service approach allows the manufacturing system to generate its own coding information using existing capabilities, eliminating the need for complex external coding devices or procedures.

Inventive Principle:
Principle #25Self-service

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

Enables cost-effective mass production of measurement systems with reduced production complexity, precise encoding, and flexible scale arrangement, ensuring accurate and reliable angle or distance measurements.

Implementation Method 1

The irreversible destruction of the conductive connection between the corresponding electrodes on the insulator substrate occurs similarly to a fuse, whereby the thermal conductivity of the substrate material and the conductor material must be taken into account to ensure sufficient power is supplied to heat the electrical connection until it melts.

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP2994722B1Scale for a length measuring system, length measuring system and method for producing a length measuring system
Publication Date: 2020.09.30 HAMILTON BONADUZ AG
  • EP2994722B1 patent drawingFigure 1~2
  • EP2994722B1 patent drawingFigure 3~4
  • EP2994722B1 patent drawingFigure 5~6

AI summary

The invention provides a scale (1) for a length measuring system for recording the absolute values of angles or distances, which scale has at least one track (3, 4) for identifying length or angle information and coding (5) for identifying the scale (1) on a printed circuit board (2), wherein the coding (5) has at least one coding element (6) comprising at least two electrodes (7, 9, 14) and a conductive connection (8) between the electrodes (7, 9, 14) on an insulator substrate, wherein the electrical connection (8) can be irreversibly destroyed by applying an electrical current.