Hybrid Magnetic-Piezo Speaker Drive for Compact Audio Output
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Solution Overview
Problem
Existing sound production solutions in portable electronic devices face challenges in achieving a suitable combination of small size, good efficiency at all audio frequencies, and affordable controlling electronics, particularly with piezoelectric vibrators requiring high voltage amplifiers.
Innovation Solution
The use of a common audio amplifier to drive both a piezoelectric vibrator and a magnetic vibrator, where the magnetic vibrator is composed of permanent magnets and an induction coil, and the piezoelectric vibrator generates vibrations from deformations of piezoelectric material, allowing for efficient sound production across all audio frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a piezoelectric vibrator is used for sound production, then good efficiency at high frequencies is achieved, but the controlling electronics become complex and expensive due to high voltage requirements
Solution Approach 1:
The patent combines a magnetic vibrator and a piezoelectric vibrator into a single sound production system, where the magnetic vibrator handles low-frequency sounds and the piezoelectric vibrator handles high-frequency sounds. This merging allows the system to achieve broad frequency coverage while using a common audio amplifier, reducing the complexity of controlling electronics compared to using a piezoelectric vibrator alone which would require high voltage amplification.
Solution Approach 2:
The patent segments the audio frequency range by assigning different vibrators to different frequency bands. The magnetic vibrator is responsible for low-frequency sound production, while the piezoelectric vibrator handles high-frequency sounds. This segmentation allows each vibrator to operate in its optimal frequency range, achieving good overall efficiency without requiring complex high-voltage control electronics for the entire frequency spectrum.
2Ease of manufacture
If a magnetic vibrator is used for sound production, then affordable controlling electronics are achieved, but efficiency at high frequencies deteriorates
Solution Approach 1:
The patent merges a magnetic vibrator and a piezoelectric vibrator into a hybrid sound production system. The magnetic vibrator provides affordable controlling electronics and handles low-frequency efficiency, while the piezoelectric vibrator supplements high-frequency performance. This combination resolves the contradiction by achieving both affordability and high-frequency efficiency through collaborative operation of two different vibrator types.
Solution Approach 2:
The patent employs a composite approach by combining two different vibrator technologies (magnetic and piezoelectric) into a single sound production system. This composite system leverages the strengths of each type: the magnetic vibrator's affordability and low-frequency performance, and the piezoelectric vibrator's high-frequency efficiency, achieving overall superior performance that neither could achieve alone.
3Volume of moving object
If the device size is reduced for portability, then small form factor is achieved, but the space for sound production components becomes limited
Solution Approach 1:
The patent merges the sound production functions of magnetic and piezoelectric vibrators into a compact integrated arrangement. By combining these two vibrator types in a space-efficient configuration, the system achieves effective sound production across all audio frequencies without requiring a large device volume, thus resolving the contradiction between small form factor and adequate component space.
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 solution enables efficient sound production across all audio frequencies in a compact form factor, reducing the complexity and cost of controlling electronics by allowing the use of lower voltage amplifiers and leveraging the complementary frequency responses of magnetic and piezoelectric vibrators.
Implementation Method 1
The vibrations are generated by supplying an electrical signal to the induction coil, whereby its varying magnetic field together with the fields of the permanent magnets generates forces that displace the parts of the magnetic vibrator relative to each other.
Implementation Method 2
An electrical signal supplied to the piezoelectric material causes in the material quick, reversible deformations, which cause the cover part to vibrate all over so as to function as an acoustic element.
Data Source
Figure 1~4
AI summary
An arrangement for producing sound in an electronic device comprises a magnetic vibrator (101) comprising a first part (203) and a second part (204) provided with permanent magnets, and at least one induction coil (205). The arrangement further comprises a piezoelectric vibrator (102) comprising piezoelectric material for generating audio-frequency vibrations resulting from deformations of the material by supplying to said material a second electrical signal. The magnetic vibrator (101) and the piezoelectric vibrator (102) have a common audio amplifier (103). Said first and second electrical signal are supplied from the same audio output (104) to the magnetic vibrator (101) and the piezoelectric vibrator (102).