BDD pH Electrode Laser Patterning to Reduce Heating and Alkali Error

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Solution Overview

Problem

Conventional pH electrodes are fragile, prone to 'alkali errors', and require frequent maintenance, especially in applications with low conductivity or heavy metals, and the laser machining process for boron-doped diamond (BDD) pH sensors can lead to heating and inefficiencies in manufacturing.

Innovation Solution

A method for manufacturing BDD pH electrodes with a pH-sensitive carbon region using controlled laser machining to create sp2 carbon structures and quinone-like groups, optimizing pulse overlap and pattern selection to reduce heating and manufacturing time, resulting in a more robust and accurate electrode.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional glass pH electrodes are used, then pH measurement is achieved, but the electrodes are fragile and require frequent maintenance

Engineering Contradiction:
Improveelectrode durabilityVSAvoidmaintenance frequency
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent changes the material parameter of the electrode from conventional glass to boron-doped diamond (BDD), which fundamentally alters the mechanical and chemical properties. BDD provides exceptional hardness, chemical inertness, and electrochemical stability, eliminating the fragility and maintenance issues of glass electrodes while maintaining pH measurement functionality through laser-induced sp2 carbon structures.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite structure by combining boron-doped diamond (BDD) bulk material with laser-induced sp2 carbon surface structures. The BDD bulk provides mechanical strength and chemical stability, while the sp2 carbon surface regions provide pH-sensitive electrochemical activity, achieving both durability and measurement accuracy.

Inventive Principle:
Principle #40Composite materials

2Measurement precision

If laser machining is used to create pH-sensitive regions on BDD, then measurement accuracy is improved, but heating and manufacturing time increase

Engineering Contradiction:
ImprovepH measurement accuracyVSAvoidmanufacturing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent employs periodic pulsed laser machining instead of continuous laser exposure. By using short laser pulses with adequate cooling intervals, the process creates the necessary sp2 carbon structures while allowing heat dissipation between pulses. This prevents excessive heating and reduces total manufacturing time compared to continuous machining or multiple repeated passes.

Inventive Principle:
Principle #19Periodic action

3Measurement precision

If repeated laser machining is performed to create array patterns, then pH sensitivity is enhanced, but heat generation and process time increase

Engineering Contradiction:
ImprovepH sensing capabilityVSAvoidlaser-induced heating
Core Design Contradiction:
Measurement precisionVSTemperature

Solution Approach 1:

The patent uses periodic pulsed laser machining to create array patterns of pH-sensitive regions. The pulsed nature allows thermal diffusion and cooling between pulses, preventing heat accumulation. This enables the creation of multiple sp2 carbon regions (arrays) without excessive heat generation, enhancing pH sensitivity while controlling temperature.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent segments the laser machining process into discrete pulses and spatially distributes the sp2 carbon structures as arrays across the BDD surface. This segmentation allows each pulse to create isolated sensitive regions with adequate thermal management, avoiding the heat concentration that would occur with continuous machining of the entire area.

Inventive Principle:
Principle #1Segmentation

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 robust, low-maintenance pH electrode with improved accuracy across various pH ranges, reducing alkali errors and manufacturing time, while maintaining precision in low conductivity and buffer capacity solutions.

Implementation Method 1

a carbon region is laser machined upon the measurement electrode to create a pH sensitive region

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

The carbon region comprises sp2 carbon materials that can include diamond-like materials doped with boron (BDD)... The carbon region has oxidized carbon structures and or quinone-like groups

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 3

A pulse overlap modification is determined to reduce heating during a laser machining process

Methodology Applied
Scientific EffectLaser heating: Laser

Data Source

PatentEP4103939B1Ph electrode with boron doped diamond region
Publication Date: 2024.12.11 HACH
  • EP4103939B1 patent drawingFigure 1
  • EP4103939B1 patent drawingFigure 2A~2C
  • EP4103939B1 patent drawingFigure 3A~3C

AI summary

A method for manufacturing a pH electrode with a carbon region, including: determining at least one pulse overlap modification for a laser pulse used when machining the carbon region; selecting a pattern for machining the carbon region; and machining a sp2 carbon region having the at least one pulse overlap modification and in the selected pattern by pulsing a laser onto a BDD (boron doped diamond) electrode surface in the selected pattern with the at least one pulse overlap modification.