Microchannel Plate Backscatter Layer for First Strike Efficiency

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Solution Overview

Problem

Conventional microchannel plates (MCPs) in night vision systems have less than ideal first strike efficiency at the input surface due to the less than 100% open area ratio and the poor secondary emission coefficient of the contact metal electrode, leading to reduced low-light sensitivity and performance.

Innovation Solution

The MCP is configured with channel openings that have an electron backscatter layer formed between a metal contact layer and a secondary electron booster layer, which scatters primary electrons onto the booster layer, increasing the number of first strike electrons and improving the first strike efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a metal contact layer is used at the input surface of the MCP, then electrical conductivity is provided for electron acceleration, but the poor secondary emission coefficient of the metal reduces the number of first strike electrons

Engineering Contradiction:
Improvefirst strike efficiencyVSAvoidelectrode material selection
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies composite materials by combining a metal contact layer with a high secondary emission coefficient material layer at the input surface of the MCP. This composite structure provides both the electrical conductivity of the metal and the high secondary emission coefficient of the other material, thereby increasing the number of first strike electrons while maintaining proper electron acceleration. The composite layering resolves the contradiction between needing metal for conductivity and needing high secondary emission material for electron multiplication.

Inventive Principle:
Principle #40Composite materials

2Reliability

If the open area ratio of the MCP is increased to improve sensitivity, then more electrons can enter the channels, but the structural integrity and channel definition may be compromised

Engineering Contradiction:
Improvelow-light sensitivityVSAvoidchannel structure integrity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by enhancing only the input surface region of the MCP channels with a high secondary emission coefficient material layer, rather than modifying the entire channel structure. This localized enhancement increases first strike efficiency and low-light sensitivity at the critical input interface without requiring changes to the overall channel geometry or structural integrity. The rest of the channel maintains its original precise manufacturing specifications.

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 improved first strike efficiency enhances the signal-to-noise ratio (SNR) of the image intensifier, increasing its low-light sensitivity and performance while reducing noise and variation in electron multiplication.

Implementation Method 1

an electron backscatter layer formed between a metal contact layer and a secondary electron booster layer to scatter primary electrons onto the booster layer and amplify resulting first strike electrons

Methodology Applied
Scientific EffectElectron backscatter: Scattering

Implementation Method 2

a secondary electron booster layer... to scatter primary electrons onto the booster layer and amplify resulting first strike electrons

Methodology Applied
Scientific EffectSecondary electron emission: Photoelectric Effect

Data Source

PatentEP4254463B1Microchannel plate and method of making the microchannel plate with an electron backscatter layer to amplify first strike electrons
Publication Date: 2025.05.07 ELBIT SYSTEMS OF AMERICA LLC
  • EP4254463B1 patent drawingFigure 1~3
  • EP4254463B1 patent drawingFigure 4~5
  • EP4254463B1 patent drawingFigure 6

AI summary

A night vision system along with an image intensifier tube having a microchannel plate and method of forming the microchannel plate are provided. The microchannel plate comprises a plurality of spaced channels extending through the microchannel plate, wherein each channel sidewall surface near the input face of the microchannel plate comprises a series of layers formed thereon. The input face of the microchannel plate, as well as the sidewall surfaces of each channel near the input surfaces, are configured with an electron backscatter layer arranged between a contact metal layer and a secondary electron booster layer. When formed partially into the channel openings near the input face, the electron backscatter layer and overlying secondary electron booster layer are configured circumferentially around the sidewall surfaces and extend radially inward toward a central axis of each channel.