Phase Modulation Module Heat Path for Light Resistance Stability

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Solution Overview

Problem

Existing phase modulation elements face issues with light resistance and plane shape changes due to heat generation, which are not adequately addressed by using a sapphire cover glass layer, leading to potential damage and distortion.

Innovation Solution

A phase modulation module with a heat sink, housing portion, reflection-type phase modulation element, and filling material, where the cover member is made of sapphire or diamond, and the filling material is in contact with the cover member's peripheral edge, forming an efficient heat dissipation path to the heat sink.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a sapphire cover glass layer is used to dissipate heat, then heat diffusion is improved, but light resistance and plane shape stability are insufficient under high light amounts

Engineering Contradiction:
Improveheat dissipationVSAvoidlight resistance
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent employs a composite structure combining sapphire cover member with high-thermal-conductivity filling material (diamond, cubic boron nitride, or silicon carbide) to create a multi-material heat dissipation system. This composite approach leverages the optical transparency of sapphire while adding superior thermal conduction pathways through the filling material, achieving both heat dissipation and light resistance requirements simultaneously.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The high-thermal-conductivity filling material acts as an intermediary between the sapphire cover member and the heat sink. It mediates heat transfer from the liquid crystal layer through the sapphire cover to the heat sink, enhancing the overall thermal conduction pathway without interfering with the optical function of the sapphire cover glass.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Temperature

If a sapphire cover glass layer is used, then heat diffusion is enhanced, but plane shape distortion occurs under temperature rise

Engineering Contradiction:
Improveheat diffusionVSAvoidplane shape stability
Core Design Contradiction:
TemperatureVSShape

Solution Approach 1:

The patent changes the thermal conductivity parameter of the cover structure by introducing high-thermal-conductivity filling material (diamond, cubic boron nitride, or silicon carbide) with thermal conductivity values significantly higher than sapphire. This parameter change creates more uniform heat distribution across the cover member, reducing thermal gradients that cause plane shape distortion.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The filling material is strategically placed in contact with the peripheral edge portion of the sapphire cover member to create localized high-thermal-conductivity pathways. This local quality enhancement at the periphery provides additional heat dissipation routes, preventing heat accumulation that would otherwise cause localized thermal expansion and plane shape distortion.

Inventive Principle:
Principle #3Local quality

3Temperature

If heat dissipation is increased through cover glass, then temperature control is improved, but structural complexity increases

Engineering Contradiction:
Improvetemperature controlVSAvoidstructure complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The filling material serves multiple functions simultaneously: it enhances thermal conduction from the sapphire cover to the heat sink, provides mechanical support to the sapphire cover member, and fills the housing portion to prevent voids. This multi-functionality achieves improved temperature control without proportionally increasing structural complexity.

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

Solution Approach 2:

The patent merges the heat dissipation function with the existing housing portion structure. The filling material is integrated into the housing portion, combining the structural support function of the housing with the thermal conduction function of the filling material, thereby achieving enhanced temperature control without adding separate complex structures.

Inventive Principle:
Principle #5Merging (Combining)

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

Enhances light resistance and suppresses plane shape changes by effectively dissipating heat, preventing damage and distortion in the phase modulation element.

Implementation Method 1

the cover member is formed of sapphire or diamond. As a result, a thermal conductivity of the cover member can be increased, and the heat generated in the vicinity of the center of the liquid crystal layer can be efficiently transferred to the peripheral edge portion of the cover member

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

the filling material is in contact with at least a part of the peripheral edge portion of the cover member and the housing portion. As a result, the heat transferred to the peripheral edge portion of the cover member can be efficiently transferred to the housing portion

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

the housing portion is thermally connected to the heat sink. As a result, the heat transferred to the housing portion can be discharged to the heat sink

Methodology Applied
Scientific EffectHeat dissipation: Heat Sink

Data Source

PatentEP4668004A1Phase modulation module, phase modulation device, and method for manufacturing phase modulation module
Publication Date: 2025.12.24 HAMAMATSU PHOTONICS KK
  • EP4668004A1 patent drawingFigure 1
  • EP4668004A1 patent drawingFigure 2
  • EP4668004A1 patent drawingFigure 3

AI summary

A phase modulation module includes a heat sink, a housing portion that has a side wall portion formed in a frame shape and thermally connected to the heat sink, and a reflection-type phase modulation element and a filling material disposed inside the side wall portion. The phase modulation element includes a circuit board disposed on the heat sink, a liquid crystal layer disposed on a side opposite to the heat sink with respect to the circuit board, and a cover member formed of sapphire or diamond in a plate shape and disposed on a side opposite to the heat sink with respect to the liquid crystal layer. The filling material is in contact with at least a part of a peripheral edge portion of the cover member and the housing portion.