Membrane Light Detector Electrode Post Geometry for Reliable Connections

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Solution Overview

Problem

The existing light detectors face electrical connection errors due to stress concentration at the intersection of the electrode post and substrate, leading to potential connection failures.

Innovation Solution

The design incorporates a membrane with first and second electrode posts featuring tubular shapes and flange portions with sloped surfaces, ensuring secure electrical connections by reducing stress concentration and deformation, and includes a resistance layer divided in beam portions to enhance thermal management and connection reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the electrode post has a cylindrical shape with vertical intersection to the substrate surface, then the structure is simple and easy to manufacture, but stress concentration occurs at the intersection portion leading to electrical connection errors

Engineering Contradiction:
Improveease of manufactureVSAvoidreliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The electrode post is designed with a tapered shape where the outer surface intersects the substrate surface at a gradual angle rather than vertically. This curved/tapered geometry distributes stress along the intersection portion, preventing stress concentration and eliminating electrical connection errors while maintaining manufacturing feasibility

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The shape parameters of the electrode post are modified from a cylindrical form with vertical intersection to a tapered form with angled intersection. This parameter change in the geometric configuration reduces stress concentration at the substrate interface, improving connection reliability without significantly complicating the manufacturing process

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the wiring layer is electrically connected to the electrode post in the connection portion, then electrical connection is achieved, but stress concentration at the intersection causes connection errors

Engineering Contradiction:
ImprovereliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The tapered electrode post creates a gradual transition zone that distributes mechanical stress away from the wiring layer connection point. This curved geometry allows the wiring layer to be connected reliably without experiencing stress concentration, maintaining connection integrity while avoiding the need for additional protective structures

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Temperature

If the membrane is disposed to form a void space between the membrane and substrate surface, then thermal performance is improved, but connection reliability deteriorates due to stress concentration

Engineering Contradiction:
Improvethermal performanceVSAvoidreliability
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The tapered electrode post design resolves the contradiction by distributing stress along the angled intersection with the substrate. This allows the membrane to maintain its void space configuration for optimal thermal performance while the gradual stress distribution prevents connection failures at the electrode post interface

Inventive Principle:
Principle #14Spheroidality (Curvature)

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

This configuration effectively suppresses electrical connection errors, secures electrical connections, and improves the thermal performance of the light detector by preventing heat escape through the beam portions.

Implementation Method 1

a resistance layer having an electrical resistance depending on a temperature

Methodology Applied
Scientific EffectTemperature-dependent electrical resistance: Electrical Resistance

Data Source

PatentEP3667269B1Light detector
Publication Date: 2024.09.18 HAMAMATSU PHOTONICS KK
  • EP3667269B1 patent drawingFigure 1
  • EP3667269B1 patent drawingFigure 2
  • EP3667269B1 patent drawingFigure 3

AI summary

A light detector includes a substrate, a membrane disposed on a surface of the substrate, a first electrode post supporting the membrane, and a second electrode post supporting the membrane. The first electrode post includes a first main body portion having a tubular shape spreading from a first electrode pad toward a side opposite to the substrate, a first bottom portion provided in an end portion at the side of the substrate in the first main body portion, and a first flange portion provided in an end portion at the side opposite to the substrate in the first main body portion. The first flange portion is provided with a first sloped surface inclined so as to approach the substrate as it goes away from the first main body portion. A first wiring layer reaches an inner surface of the first main body portion through the first sloped surface. The second electrode post and the second wiring layer are formed similarly to the first electrode post and the first wiring layer.