Optical Cochlear Implant Laser Diode Control
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Solution Overview
Problem
Optical cochlear implants require significantly higher electrical power when using the same temporal excitation patterns as electrical cochlear implants, leading to energy overloading when activating multiple areas of the cochlea simultaneously, especially during sound frequency spectrum transmission.
Innovation Solution
The method involves controlling laser diodes with low pulselet duty cycles of no more than 25% and nesting pulselets in time to limit the number of simultaneously activated laser diodes, using pulselet repetition frequencies between 5 kHz and 200 MHz, and coding volume through duty cycles, allowing for efficient neural activation of multiple cochlear areas without overloading the energy source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the same temporal excitation patterns as electrical cochlear implants are used, then neural activation of multiple cochlear areas is achieved, but electrical power consumption increases significantly leading to energy source overload
Solution Approach 1:
The excitation signal is segmented into multiple pulselets within each pulse period, where each pulselet activates a different subset of laser diodes. This segmentation allows the total neural activation task to be divided into smaller temporal segments, reducing the number of simultaneously active laser diodes and thus lowering peak power consumption while maintaining overall activation effectiveness
Solution Approach 2:
The system employs periodic pulse excitation with duty cycles of 25% or less, where laser diodes are activated in repeating cycles rather than continuously. This periodic action allows inactive laser diodes to recover and reduces average power consumption while maintaining effective neural activation through repeated stimulation cycles
2Loss of information
If multiple laser diodes are activated simultaneously to transmit sound frequency spectrum, then comprehensive auditory information is provided, but the number of simultaneously active laser diodes increases causing energy source overload
Solution Approach 1:
The system dynamically adjusts which laser diodes are activated in each pulselet based on the sound frequency spectrum requirements. Rather than statically activating all diodes simultaneously, the activation pattern changes dynamically across multiple pulselets, ensuring comprehensive frequency coverage while limiting the number of simultaneously active diodes to prevent power overload
Solution Approach 2:
Multiple pulselets are nested within each pulse period, with each pulselet containing a subset of laser diode activations. This nesting structure allows comprehensive frequency spectrum transmission to be achieved through the cumulative effect of nested pulselets, while each individual pulselet maintains low power consumption by activating only a subset of diodes
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 approach reduces the electrical power required for neural activation, enabling efficient transmission of sound frequency spectra, even during high-volume noise, by limiting the number of simultaneously active laser diodes and optimizing energy usage, thus preventing energy source overload.
Implementation Method 1
The laser diodes are each controlled in several separate pulselets... to generate laser light and couple it into different optical fibers
Implementation Method 2
couple it into different optical fibers which are arranged and configured to guide the laser light into different light-sensitive areas of a cochlea
Data Source
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AI summary
When operating an optical cochlear implant with multiple laser diodes (7), the laser diodes (7), which are assigned to different sound frequencies, are controlled by a signal describing a sound frequency spectrum in order to generate laser light (10) and couple it into different optical fibers (11). The optical fibers (11) are designed to guide the laser light (10) to different light-sensitive areas (24) of a cochlea (23). The laser diodes (7) are each controlled in several separate pulselets (19), none of which individually results in neural activation of the light-sensitive areas (24) of the cochlea (23). The duty cycles of the pulselets (19) do not exceed 25%; and the pulselets (19) in which different laser diodes (7) are controlled are interleaved in time such that no more than a quarter of the laser diodes (7) are controlled simultaneously.