Laser-Sealed Thermoplastic Sound Channels in Hearing Devices
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for sealing unwanted sound channels in hearing devices are inefficient, as expanding foams are difficult to control, silicone glue is sensitive to temperature and humidity, and double adhesive tapes are limited to small gaps, leading to issues with acoustic feedback and increased manufacturing costs.
Innovation Solution
A method using a thermoplastic material element that is transformed from a solid to a liquid state with laser light to seal sound channels, allowing precise filling and controlled cooling to achieve a reliable seal, applicable to hearing devices of any size without the need for additional storage or material waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If expanding closed-cell-foam is used to block sound path, then sound channel blocking is achieved, but control during manufacturing becomes difficult
Solution Approach 1:
The patent changes the physical state parameter of the sealing material from expanded foam (gas-filled cells) to thermoplastic material that can be melted and solidified. This allows precise control over the sealing process by controlling temperature and melting/solidification parameters, eliminating the unpredictability of foam expansion while maintaining effective sound blocking.
Solution Approach 2:
The patent utilizes phase transitions of thermoplastic material between solid and liquid states controlled by temperature. The material is heated to melt and flow into the sound channel, then cooled to solidify and seal the channel. This phase transition approach provides controlled, repeatable manufacturing unlike foam expansion, while achieving reliable sound isolation.
2Reliability
If silicone glue is used to seal sound channel, then acoustic path blocking is achieved, but handling becomes difficult due to viscosity changes
Solution Approach 1:
The patent changes the operational parameter of the sealing material from temperature-sensitive glue (whose viscosity changes with temperature and time) to thermoplastic material whose flow properties are controlled solely by temperature. The material maintains stable handling characteristics until heated, then flows predictably during sealing, eliminating the handling difficulties associated with glue viscosity changes.
Solution Approach 2:
The patent replaces the chemical-based sealing mechanism (glue adhesion that requires careful timing and temperature control) with a thermal-based mechanism (thermoplastic melting and solidification). This substitution eliminates the need to manage glue viscosity and curing time, simplifying the manufacturing process while achieving reliable acoustic sealing.
3Reliability
If glue is used for sealing, then sound channel blocking is achieved, but storage requirements increase due to temperature and humidity sensitivity
Solution Approach 1:
The patent changes the environmental stability parameter of the sealing material from humidity and temperature sensitive (glue requiring controlled storage) to thermally stable (thermoplastic material). The thermoplastic material can be stored at room temperature without degradation, eliminating the need for specialized storage conditions and reducing logistical complexity.
4Reliability
If double adhesive tapes are used to block sound path, then small gaps are sealed, but application to larger openings becomes limited
Solution Approach 1:
The patent creates a universal sealing solution using thermoplastic material that can adapt to any sound channel geometry or size. The material can be melted and injected into small gaps like tapes, or poured into large openings like foam, providing a single method that replaces multiple sealing techniques and achieves reliable acoustic isolation across all applications.
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 method provides a cost-effective, controlled, and precise sealing of sound channels, reducing acoustic feedback and manufacturing complexity, while being adaptable to various hearing device designs and sizes, including those with microphones and speakers.
Implementation Method 1
applying a laser light to the element to thereby activate the element to change from the solid state to a liquid state
Implementation Method 2
the element being heated by a laser light and thereby transformed into a liquid state
Implementation Method 3
allowing cooling of the element thereby a change of the element from the liquid state to solid state
Implementation Method 4
the element changes its state upon the laser light application and thereby seals the sound channel
Data Source
AI summary
A method for manufacturing a hearing device is disclosed. The hearing device comprises a speaker, a first chamber, and a sound channel arranged between the first chamber and the surroundings of the hearing device or a second chamber. An element of a thermoplastic material being in a solid state is arranged in the sound channel. A laser light is applied to the element to thereby activate the element to change from the solid state to a liquid state. The element then changes from the solid state to the liquid state filling out a cross-section of the sound channel and thereby sealing the sound channel. Finally, cooling of the element is allowed leading to a change of the element from the liquid state to solid state while filling out the cross-section of the sound channel.