Acoustic Output Devices
Patent No. US12108208 (titled "Acoustic Output Devices") was filed by Shenzhen Shokz Co Ltd on Sep 14, 2022.
What is this patent about?
’208 is related to the field of acoustic output devices, specifically those used in open-ear applications. Traditional open-ear devices suffer from significant sound leakage due to their open structure. Existing solutions often involve placing a speaker in an acoustic cavity with openings to create a directional sound field. However, design constraints can prevent opening the back of the cavity, leading to resonance, standing waves, and a narrowed frequency response, ultimately increasing sound leakage.
The underlying idea behind ’208 is to suppress standing waves within the back cavity of an acoustic output device to broaden its frequency response and reduce sound leakage. This is achieved by incorporating a curved structure connecting different side walls of the back cavity. This curved structure disrupts sound reflection patterns, preventing standing wave formation and effectively compressing the cavity volume.
The claims of ’208 focus on an acoustic output device comprising an acoustic driver with a diaphragm and magnetic circuit structure, and a housing structure forming a back cavity. The key feature is that the side walls of the back cavity are connected by a curved structure . The housing includes at least one sound outlet hole acoustically coupled with the back cavity, allowing sound radiated from the back of the driver to exit the device.
In practice, the diaphragm vibrates, radiating sound from both its front and back sides. The sound from the back side enters the back cavity. The curved structure within the cavity disrupts the formation of standing waves, which would otherwise create undesirable resonance peaks in the frequency response. By suppressing these standing waves and compressing the cavity volume, the device achieves a wider frequency range for the sound emitted from the back cavity.
This design differs from prior approaches that rely on simple acoustic cavities, which are prone to standing waves and limited frequency responses. By strategically placing the curved structure, the invention ensures that the sound from the back cavity interferes constructively with the sound from the front of the diaphragm, leading to reduced sound leakage in the far field. The addition of a second sound outlet hole opposite the first further enhances this effect.
How does this patent fit in bigger picture?
Technical landscape at the time
In the late 2010s when ’208 was filed, acoustic devices were typically implemented using established speaker designs and materials. At a time when miniaturization was a key engineering constraint, systems commonly relied on carefully tuned acoustic cavities to manage sound pressure levels and frequency responses, especially in open-ear designs where sound leakage was a known issue.
Novelty and Inventive Step
The examiner approved the application because prior art, specifically Shang et al. and Shi, failed to teach or suggest the claimed limitation of "the side walls of the back cavity are connected to each other by a curved structure." While Shang teaches a loudspeaker module with a peripheral housing, a diaphragm sheet, and a side sound hole, it does not disclose the curved structure connecting the side walls of the back cavity.
Claims
There are 18 claims in total, with claim 1 being the only independent claim. Independent claim 1 is directed to an acoustic output device comprising an acoustic driver and a housing structure. The dependent claims generally elaborate on specific features and configurations of the acoustic output device described in the independent claim, such as the shape and location of sound outlet holes, the inclusion of acoustic damping structures, and the presence of protective structures.
Key Claim Terms New
Definitions of key terms used in the patent claims.
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Date
Description
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US12108208
- Application Number
- US17932288
- Filing Date
- Sep 14, 2022
- Status
- Granted
- Expiry Date
- Jun 6, 2041
- External Links
- Slate, USPTO, Google Patents