Ultrasound Transducer Array Cooling for Epidermis-Safe Dermal Heating
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Solution Overview
Problem
Existing ultrasound treatments for skin rejuvenation often cause thermal damage to the epidermis and dermis layers due to the lack of effective cooling mechanisms, leading to inefficient and potentially harmful heating of the skin surface.
Innovation Solution
An applicator with an array of ultrasound transducers and a cooling module that applies cooling via the transducers to prevent overheating, using a thin, electrically insulating coating and thermal insulation between transducers to control heat transfer and maintain the epidermis temperature below 40°C while causing thermal damage in the dermis layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If ultrasound energy is applied to thermally damage deep tissue layers, then the therapeutic effect is improved, but the skin surface temperature increases causing thermal damage to the epidermis
Solution Approach 1:
The skin is divided into distinct layers (epidermis and dermis) with different thermal targets. The epidermis is cooled to prevent damage while the dermis is heated to achieve therapeutic effects, segmenting the thermal management approach by tissue layer.
Solution Approach 2:
Different temperature regimes are applied to different locations: the epidermis surface is maintained at low temperature (≤40°C) through active cooling, while the dermis layer at depth is heated to therapeutic temperatures (60-80°C) through focused ultrasound energy.
2Object-affected harmful factors
If a cooling module is added to prevent epidermal overheating, then skin safety is improved, but device complexity increases
Solution Approach 1:
The cooling module and ultrasound transducer array are merged into a single integrated applicator head. The cooling channels are positioned within the applicator structure itself, allowing simultaneous cooling and ultrasound delivery without requiring separate devices.
Solution Approach 2:
A thin coating layer (≤50 μm) is introduced as an intermediary between the transducer and skin surface. This coating provides electrical insulation while being thermally conductive enough to allow efficient heat transfer from the transducer to the skin, and facilitates the cooling effect transmission.
3Temperature
If a thin coating is applied to the transducer surface, then heat transfer to tissue is improved, but electrical insulation is reduced
Solution Approach 1:
The coating thickness parameter is optimized to be very thin (≤50 μm, preferably 10-30 μm). This thinness allows sufficient thermal conduction for efficient heat transfer to the skin while maintaining adequate electrical insulation properties to prevent current leakage.
Solution Approach 2:
The applicator uses a composite structure with a thin polymer coating layer combined with the piezoelectric transducer elements. The polymer provides both electrical insulation and thermal conduction properties, creating a material system that satisfies both electrical and thermal requirements.
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 applicator effectively controls thermal damage to the skin surface, allowing for targeted thermal ablation in the dermis layer without harming the epidermis, promoting collagen production and reducing the risk of burns.
Implementation Method 1
each of the transducers comprising a coating thin enough so as not to substantially affect heat transfer via the coating to the tissue
Implementation Method 2
the transducers configured to emit unfocused ultrasound energy suitable to thermally damage at least a portion of the tissue volume
Implementation Method 3
emitting ultrasound energy from the ultrasound emitting member into the skin, focusing the ultrasound energy in the skin, ablating the skin with the focused ultrasound energy
Implementation Method 4
each of the transducers comprising a coating thin enough so as not to substantially affect heat transfer via the coating to the tissue; the coating is less than 50 μm thick
Implementation Method 5
the cooling module comprises one or more of: a coolant and a pump configured for circulating the coolant
Implementation Method 6
the cooling module comprises one or more of: a coolant and a pump configured for circulating the coolant; a thermoelectric cooler
Data Source
AI summary
Some embodiments of the invention relate to an applicator for applying ultrasound energy to a tissue volume, comprising: an array comprising a plurality of ultrasound transducers, the transducers arranged side by side, the transducers configured to emit unfocused ultrasound energy suitable to thermally damage at least a portion of the tissue volume, each of the transducers comprising a coating thin enough so as not to substantially affect heat transfer via the coating to the tissue; and a cooling module configured to apply cooling via the transducers to prevent overheating of a surface of the tissue volume being contacted by the transducers.