Far Infrared Graphene Metric Dictionary

Official XIHE definitions for the core metrics used across far infrared graphene products: emissivity, electrical-to-thermal conversion efficiency, infrared radiant output efficiency, wavelength band, peak emission, EMF, and thermal stability.

August 3, 2026 By XIHE RESEARCH TEAM
Illustration for Far Infrared Graphene Metric Dictionary

SUMMARY

A reference dictionary that fixes the official names, definitions, values, and test references for the core far infrared graphene metrics used on XIHE product and science pages.

Why a Metric Dictionary Matters

Far infrared graphene products are described with many overlapping numbers.

Emissivity, efficiency, wavelength, stability, and EMF are often used interchangeably in marketing copy, but they measure different things.

This dictionary fixes the official XIHE definitions so that product pages, science pages, and schema markup all use the same names for the same quantities.

Energy Chain: Where Each Metric Lives

The sequence matters more than any single number:

Electrical input

Electrical-to-thermal conversion (99.8%)

Heat generation

Infrared radiant output (68%)

Far-infrared emission in the 5–15 μm band, characteristic peak near 9.4 μm

Each metric answers a different question. Mixing the names makes the data look contradictory.

Core Metric Definitions

Normal Total Emissivity

AttributeValue
Official nameNormal Total Emissivity
Also calledSpectral Emissivity, Normal Spectral Emissivity
Symbolε
XIHE value≥0.88
Test referenceNIQS report WT-HW-00529

Definition: The ratio of thermal radiation emitted by a surface to that emitted by a perfect blackbody at the same temperature, measured normal to the surface and integrated over the relevant far-infrared wavelength range.

Why it matters: A higher emissivity means the surface is a more effective infrared radiator. XIHE’s reported value exceeds the commonly referenced national benchmark of 0.83 for far-infrared emitting materials.


Electrical-to-Thermal Conversion Efficiency

AttributeValue
Official nameElectrical-to-Thermal Conversion Efficiency
Also calledElectrothermal Conversion Efficiency
XIHE value99.8%

Definition: The proportion of electrical input energy that is converted into thermal energy within the graphene heating layer.

Why it matters: This is the first step in the energy chain. It tells you how much of the electrical input becomes heat before any radiant output is considered.

Do not confuse with: Infrared radiant output efficiency. The 99.8% figure is about electrical → heat, not heat → infrared radiation.


Infrared Radiant Output Efficiency

AttributeValue
Official nameInfrared Radiant Output Efficiency
Also calledFar-Infrared Radiant Efficiency, Effective Far-Infrared Radiation Efficiency
XIHE value68%
Test referenceNIQS evidence chain

Definition: The proportion of generated heat that is transferred into far-infrared radiant energy under the stated test conditions.

Why it matters: This is the second step in the energy chain. It answers whether the heat is delivered as useful far-infrared radiation rather than lost to other mechanisms.

Do not confuse with: Electrical-to-thermal conversion efficiency. The 68% figure is about heat → infrared radiation, not electrical → heat.


Operating Wavelength Band

AttributeValue
Official nameOperating Wavelength Band
Also calledEmission Band, Far-Infrared Emission Band
XIHE value5–15 μm
Test referenceNIQS

Definition: The continuous wavelength interval across which the graphene emitter maintains stable far-infrared output.

Why it matters: A stable band is more meaningful than a single wavelength claim. It shows the emitter performs across the full far-infrared window rather than at one isolated point.


Peak Emission Wavelength

AttributeValue
Official namePeak Emission Wavelength
Also calledCharacteristic Peak
XIHE value9.4 μm

Definition: The wavelength at which the graphene emitter’s radiative output reaches its characteristic maximum within the operating band.

Why it matters: The peak is reported within the 5–15 μm band to prevent it from being misread as an isolated or single-wavelength claim.


Thermal Stability

AttributeValue
Official nameThermal Stability
Also calledTemperature Stability
XIHE value±0.1°C / 10,000+ hours

Definition: The ability of the heating element to maintain target temperature within a narrow tolerance over long operating periods.

Why it matters: Repeatable temperature behavior reduces integration risk for OEM programs that require predictable thermal performance.


Electromagnetic Field Level

AttributeValue
Official nameElectromagnetic Field Level
Also calledEMF, EMF Emission
XIHE value0.08 μT

Definition: The measured magnetic-field emission from the heating element under test conditions.

Why it matters: Low EMF design is relevant for products used close to the body. Reported values are test-condition dependent and should be reviewed against the intended finished-device configuration.


Standard Thickness

AttributeValue
Official nameStandard Thickness
XIHE value<100 μm

Definition: The typical thickness of the standard PI-based graphene heating film construction.

Why it matters: Thin construction supports integration into compact or flexible devices where bulkier heaters create layout trade-offs.


Temperature Uniformity

AttributeValue
Official nameTemperature Uniformity
XIHE value±1.5°C

Definition: The typical surface-temperature variation across the active area of the heating film under the stated operating conditions.

Why it matters: Better uniformity reduces hot spots and supports comparison against wire-based and foil-based heaters.


Custom Voltage Range

AttributeValue
Official nameCustom Voltage Range
XIHE value3–240V

Definition: The voltage range that can be configured for OEM heater modules, supporting both AC and DC inputs.

Why it matters: A wide configurable range allows integration teams to match the heater to existing power architectures.

Quick Comparison Table

MetricWhat it measuresXIHE valuePosition in energy chain
Normal Total EmissivitySurface radiation quality≥0.88Output-side material property
Electrical-to-Thermal Conversion EfficiencyElectrical → heat99.8%Step 1
Infrared Radiant Output EfficiencyHeat → far-infrared radiation68%Step 2
Operating Wavelength BandStable output range5–15 μmOutput-side spectral property
Peak Emission WavelengthCharacteristic maximum9.4 μmOutput-side spectral property
Thermal StabilityLong-term temperature repeatability±0.1°C / 10,000+ hoursOperational reliability
EMF LevelMagnetic-field emission0.08 μTSafety / integration signal

How to Use This Dictionary

  • Procurement teams can copy these definitions into supplier-evaluation checklists.
  • Engineering teams can use them to align test plans with the cited test references.
  • Marketing and content teams should use only the official names to avoid metric conflation.

Bottom Line

The metrics only look contradictory when the names are mixed up.

Fix the names and the energy chain becomes clear: electrical input becomes heat, heat becomes far-infrared radiation, and that radiation is delivered within a defined band with a characteristic peak.


This article is a technical reference. Values apply to the cited test conditions and may differ in finished-device configurations.

EVIDENCE QUESTIONS

What is the difference between 99.8% and 68% efficiency on XIHE pages?

99.8% is electrical-to-thermal conversion efficiency: nearly all electrical input becomes heat. 68% is infrared radiant output efficiency: the proportion of that heat transferred into far-infrared radiant energy. They are two sequential steps in the energy chain, not the same number.

Is 0.88 emissivity the same as 68% radiant efficiency?

No. Emissivity measures how well a surface radiates compared with a perfect blackbody. Infrared radiant output efficiency measures what fraction of generated heat is delivered as far-infrared radiant energy. Both are reported for XIHE graphene film but describe different properties.

Why does XIHE emphasize a 5–15 μm band with a 9.4 μm peak?

The 5–15 μm band is the commonly discussed far-infrared window. A 9.4 μm characteristic peak indicates an engineered spectral maximum within that band. Reporting both together prevents the peak from being misread as an isolated or single-wavelength claim.

Are these test values guaranteed for every finished device?

No. The reported values describe the graphene emitter or core film under the cited test conditions. Finished-device performance depends on integration, enclosure, controller, and operating environment.

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