Pt Resistance Layer Structure for Wide-Temperature Electron Multipliers

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Solution Overview

Problem

Conventional atomic layer deposition (ALD) micro-channel plates (MCPs) using resistance films formed by ALD methods exhibit poor temperature characteristics, limiting their operational range from low to high temperatures, and are affected by environmental temperature variations, which is a concern for applications like photo-multiplier tubes and image intensifiers.

Innovation Solution

An electron multiplier structure is developed using a substrate with a secondary electron emitting layer and a resistance layer that includes a Pt layer with two-dimensionally arranged metal particles, which have positive temperature characteristics, to stabilize and improve the resistance value variation across a wider temperature range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a resistance film is formed by the ALD method in conventional MCPs, then the film formation precision is improved, but the temperature characteristic (temperature coefficient) of the resistance value deteriorates

Engineering Contradiction:
Improvefilm formation precisionVSAvoidtemperature characteristic
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies composite materials by combining multiple layers with different functional properties: a first resistance layer (e.g., tungsten or molybdenum) providing base resistance, a second resistance layer (e.g., platinum) with positive temperature coefficient to compensate for drift, and insulating layers (e.g., aluminum oxide) to electrically isolate the conductive layers. This multi-layer composite structure achieves both precise film formation through ALD and stable temperature characteristics across wide temperature ranges.

Inventive Principle:
Principle #40Composite materials

2Device complexity

If conventional ALD-MCP structures are used, then the manufacturing process is simplified, but the operational temperature range is limited

Engineering Contradiction:
Improvemanufacturing process complexityVSAvoidoperational temperature range
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent employs parameter changes by systematically varying the thickness, material composition, and layer configuration of the resistance films to optimize performance across different temperature ranges. The ALD process parameters (temperature, pressure, precursor flow rates) are precisely controlled to achieve the desired film properties. This enables the MCP to operate stably from cryogenic temperatures up to high temperatures while maintaining a manufacturable process.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If a single-layer resistance film is used, then the device structure is simplified, but the resistance value stability across temperature variations deteriorates

Engineering Contradiction:
Improvedevice structureVSAvoidresistance value stability
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The patent applies composite materials by combining multiple layers with different functional properties: a first resistance layer (e.g., tungsten or molybdenum) providing base resistance, a second resistance layer (e.g., platinum) with positive temperature coefficient to compensate for drift, and insulating layers (e.g., aluminum oxide) to electrically isolate the conductive layers. This multi-layer composite structure achieves both precise film formation through ALD and stable temperature characteristics across wide temperature ranges.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by assigning different functional properties to different layers: the first resistance layer provides bulk resistance, the second resistance layer with positive temperature coefficient provides temperature compensation at specific locations, and insulating layers provide electrical isolation where needed. This localized functional differentiation enables resistance value stability across temperature variations while maintaining a relatively simple overall device structure.

Inventive Principle:
Principle #3Local quality

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 configuration effectively enhances the temperature coefficient of the resistance layer, reducing current variations due to environmental temperature changes, allowing the electron multiplier to function stably across a broader temperature range, thus addressing the limitations of conventional ALD-MCPs.

Implementation Method 1

a resistance layer including a Pt layer having a plurality of metal particles comprised of a metal material whose resistance value has a positive temperature characteristic two-dimensionally arranged in a state of being separated from each other

Methodology Applied
Scientific EffectPositive temperature coefficient: Thermal Expansion

Implementation Method 2

an electron multiplier that emits secondary electrons in response to incidence of the charged particles

Methodology Applied
Scientific EffectSecondary electron emission: Photoelectric Effect

Data Source

PatentEP3648141B1Electron multiplier
Publication Date: 2024.03.06 HAMAMATSU PHOTONICS KK
  • EP3648141B1 patent drawingFigure 1A~1B
  • EP3648141B1 patent drawingFigure 2A~2C
  • EP3648141B1 patent drawingFigure 3A~3C

AI summary

The present embodiment relates to an electron multiplier having a structure configured to suppress and stabilize a variation of a resistance value in a wider temperature range. The electron multiplier includes a resistance layer sandwiched between a substrate and a secondary electron emitting layer and configured using a Pt layer two-dimensionally formed on a layer formation surface which is coincident with or substantially parallel to a channel formation surface of the substrate. The resistance layer has a temperature characteristic within a range in which a resistance value at -60°C is 10 times or less, and a resistance value at +60°C is 0.25 times or more, relative to a resistance value at a temperature of 20°C.