Elongated Loudspeaker Flat Diaphragm Coupling Cone Design
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Solution Overview
Problem
Conventional narrow loudspeakers suffer from break-up resonances in the longitudinal direction, leading to deteriorated sound quality and difficulty in reducing their width and thickness due to their elongated shape and deep diaphragm design.
Innovation Solution
The loudspeaker features an elongated flat-plate-shaped diaphragm with a coupling cone having two elongated portions arranged parallel to the diaphragm's longitudinal direction, which are designed to vibrate in conjunction with the diaphragm, and are positioned within magnetic gaps to enhance vibration and reduce thickness, along with reinforcing ribs and a damper structure for improved rigidity and reduced distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the loudspeaker uses a conventional elongated narrow design with deep diaphragm, then it can provide improved sound quality with dynamic reproduction, but it increases the width and thickness of the loudspeaker
Solution Approach 1:
The patent transitions from a conventional deep, three-dimensional diaphragm structure to a flat-plate diaphragm structure. This dimensional change allows the loudspeaker to maintain its elongated shape for stereo sound while significantly reducing both width and thickness, enabling integration into thin electronic devices without compromising sound quality
Solution Approach 2:
The patent divides the single voice coil system into two separate voice coils positioned at different locations along the elongated diaphragm. This segmentation enables independent control of each coil, allowing the flat diaphragm to vibrate in a manner that reproduces dynamic sound comparable to conventional deep designs while maintaining a thin profile
2Volume of moving object
If the loudspeaker uses a flat-plate diaphragm design, then it reduces width and thickness, but it causes break-up resonances in the longitudinal direction deteriorating sound quality
Solution Approach 1:
By dividing the diaphragm into two independently controlled sections with separate voice coils, the patent prevents break-up resonances that would occur in a uniformly driven flat plate. Each section can be driven independently, allowing the flat-plate design to maintain high sound quality without longitudinal resonances while achieving reduced width and thickness
3Area of stationary object
If the loudspeaker reduces the number of magnetic circuits to decrease width, then it simplifies structure and reduces size, but it may compromise the driving force and vibration range
Solution Approach 1:
The patent extracts the magnetic circuit from the center and positions two voice coils at opposite sides of the diaphragm, each interacting with its own magnetic gap. This extraction allows the loudspeaker to reduce width by eliminating the central magnetic structure while maintaining sufficient driving force through the distributed coil configuration
Solution Approach 2:
The patent transitions from a single central magnetic circuit to a distributed magnetic field configuration with gaps positioned at the sides. This spatial redistribution maintains the necessary magnetic flux density for driving the voice coils while reducing the overall width of the loudspeaker assembly
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 design effectively suppresses break-up resonances, achieves high sound quality, and reduces the loudspeaker's width and thickness while maintaining excellent bass reproduction and reduced distortion, making it suitable for integration into electronic devices without increasing their size.
Implementation Method 1
alternating current is applied to the voice coil 106. Then the voice coil bobbin 105 makes piston movements based on the alternating current flowing through the voice coil 106 and the magnetic field produced around the voice coil 106
Implementation Method 2
a coupling cone extending from a rear surface of the diaphragm, as viewed from the emission direction of sound waves, and including two elongated portions arranged parallel to a longitudinal direction of the diaphragm, the coupling cone vibrating in conjunction with the diaphragm
Data Source
Figure 1(a)~1(c)
Figure 2
Figure 3~4
AI summary
There is provided an elongated loudspeaker having high sound quality that is unlikely to cause break-up resonances and is capable of obtaining flat frequency characteristics. The loudspeaker includes: an elongated flat-plate-shaped diaphragm; a frame having an opening portion larger than the diaphragm; an edge placed between an inner periphery of the frame around the opening portion and an outer periphery of the diaphragm and supporting and allowing the diaphragm to easily vibrate in an emission direction of sound waves; a coupling cone extending from a rear surface of the diaphragm and including two elongated portions arranged parallel to a longitudinal direction of the diaphragm, the coupling cone vibrating in conjunction with the diaphragm; a voice coil wound around at least the two elongated portions; and a magnetic circuit that imparts, to the voice coil, driving force for generating sound waves. A distance between the two elongated portions of the coupling cone is smaller at end positions than at root positions, the end positions being far from the rear surface of the diaphragm and the root positions being close to the rear surface. The two elongated portions are of such shapes and sizes that the entire two elongated portions are included within respective magnetic gaps of the magnetic circuit when the coupling cone vibrates in conjunction with the diaphragm, the entire two elongated portions extending from the root positions to the end positions, respectively.