Segmented Filter for IPL Device Thermal Stress

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Solution Overview

Problem

Existing dermatological treatment apparatuses using intense pulse light (IPL) face issues with filters cracking due to thermal stress from increased light energy and shorter pulse separation, which limits power output and treatment speed.

Innovation Solution

A filter arrangement with multiple light energy filtering portions, positioned to reduce thermal stress, allowing higher power output and faster operation, utilizing a xenon flash lamp and a high pass filter with a cut-on value between 470-650nm to prevent harmful wavelengths from reaching the skin.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the time between pulses is reduced to increase treatment speed, then productivity is improved, but the filter is more susceptible to cracking due to thermal stress

Engineering Contradiction:
Improvetreatment speedVSAvoidfilter cracking resistance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The filter is divided into multiple separate filter portions (first filter portion, second filter portion, etc.) arranged in series within the light path. This segmentation distributes the thermal stress across multiple components rather than concentrating it in a single filter, allowing the system to operate at higher pulse frequencies without causing filter damage.

Inventive Principle:
Principle #1Segmentation

2Power

If the light power output is increased to improve treatment effectiveness, then productivity is improved, but the filter temperature increases causing mechanical stress and potential cracking

Engineering Contradiction:
Improvelight power outputVSAvoidfilter temperature
Core Design Contradiction:
PowerVSTemperature

Solution Approach 1:

The filter system is segmented into multiple filter portions that share the thermal load. Each filter portion experiences reduced individual thermal stress compared to a single filter handling the entire light power, enabling higher overall power output without exceeding the thermal tolerance of individual filter components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple filter portions act as intermediaries in the light path, collectively managing the thermal energy distribution. The series arrangement of filters creates intermediate stages for heat dissipation, preventing any single filter from experiencing excessive temperature rise.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If the time between pulses is reduced to enhance usability, then ease of operation is improved, but the filter cooling time is insufficient leading to thermal stress accumulation

Engineering Contradiction:
ImproveusabilityVSAvoidfilter cooling time
Core Design Contradiction:
Ease of operationVSDuration of action of stationary object

Solution Approach 1:

By segmenting the filter into multiple portions, the system can sustain higher pulse frequencies because the thermal burden is distributed. Each filter portion has sufficient time to cool between pulses even at reduced pulse separation intervals, maintaining filter integrity while improving operational speed and usability.

Inventive Principle:
Principle #1Segmentation

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

Enables higher power output and reduced pulse separation, allowing for faster and safer dermatological treatments without filter cracking, enhancing usability and treatment speed.

Implementation Method 1

absorption filters which absorb the harmful wavelengths

Methodology Applied
Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 2

dichroic filters which reflect the harmful wavelengths

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

a capacitor is discharged over a Xenon flash lamp such that the flash lamp emits an intense pulse of light energy

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 4

cracking due to mechanical stresses induced by the significant increase in temperature caused by the light energy

Methodology Applied
Scientific EffectThermal stress: Thermal Shock

Data Source

PatentEP3509695B1Dermatological treatment apparatus
Publication Date: 2023.11.08 IPULSE LIMITED
  • EP3509695B1 patent drawingFigure 1~2
  • EP3509695B1 patent drawingFigure 3a~3d

AI summary

The present invention relates to a dermatological treatment apparatus. Such dermatological treatments include but are not limited to hair removal, treatment of acne and lesions and also skin rejuvenation. The apparatus comprises a housing; a light emitting source provided in the housing arranged to emit light energy along an energy pathway to external of the device; and a filter arrangement positioned in the energy pathway having at least a first and a second light energy filtering portion together combining to span across the energy pathway for filtering the light energy passing to external of the device.