Patent Grant
10804591
This disclosure relates to electronics and mounting of microelectromechanical systems (MEMS) sensors in electronic devices.
Microelectromechanical systems (MEMS) sensors such as microphones have been used in portable devices, mobile phones, head sets, medical devices, laptops and other like applications and devices. Due to their size, MEMS sensors are particularly useful for low profile or thin device applications. However, there are some practical considerations that need to be accounted for. The frequency response of a MEMS microphone system, for example, under application conditions requires tuning of the dimensions of the tube opening and cavity volume located in front of the MEMS microphone's port opening. The air volume associated with the physical dimensions of the tube opening and cavity in front of the MEMS microphone's port opening determines the inherent Helmholtz resonance of the system. In the case where the MEMS microphone is held directly against a vibrating surface such as skin to measure heart sounds, the straight cylindrical tube and the air cavity do not exist. As a result, the output signal from the MEMS microphone is severely attenuated and not very useful.
A horn shaped air cavity placed in front of the MEMS microphone's port opening via a short length of open tube provides the required air volume and as a result, the MEMS microphone can sense enough signal amplitude in the sound pressure to provide reasonable signal-to-noise (SNR). Traditionally, the horn's throat would be considered the optimized location for mounting a sensing device such as a MEMS microphone. However, this may add to the overall height or length profile of the end device.
Disclosed herein are implementations of devices and methods for side mounting of microelectromechanical systems (MEMS) transducers on tapered horn antennae. A perforation or hole may be made in a sidewall of a tapered horn antenna. In an implementation, the hole may be substantially cylindrical, tapered and the like. In an implementation, the MEMS transducer is a MEMS microphone. In an implementation, a port opening of a MEMS microphone may be aligned with the hole and attached to the sidewall of the tapered horn antenna. In an implementation, the hole may be tapered with a diameter at one end substantially similar to a diameter of the port opening of the MEMS microphone and a larger diameter at another end of the hole. In an implementation, an intermediary structure may be used to connect the MEMS transducer to the hole in the tapered horn antennae. In an implementation, a tube may be used to connect the port opening of the MEMS antenna to the hole in the tapered horn antenna. In an implementation, the tube may be cylindrical, tapered, and the like. In an implementation, the tapered horn antenna may have multiple holes, each hole having an attached MEMS transducer.
The disclosure is best understood from the following detailed description when read in conjunction with the accompanying drawings and are incorporated into and thus constitute a part of this specification. It is emphasized that, according to common practice, the various features of the drawings are not to-scale. On the contrary, the dimensions of the various features are arbitrarily expanded or reduced for clarity.
The figures and descriptions provided herein may be simplified to illustrate aspects of the described embodiments that are relevant for a clear understanding of the herein disclosed processes, machines, manufactures, and/or compositions of matter, while eliminating for the purpose of clarity other aspects that may be found in typical similar devices, systems, compositions and methods. Those of ordinary skill may thus recognize that other elements and/or steps may be desirable or necessary to implement the devices, systems, compositions and methods described herein. However, because such elements and steps are well known in the art, and because they do not facilitate a better understanding of the disclosed embodiments, a discussion of such elements and steps may not be provided herein. However, the present disclosure is deemed to inherently include all such elements, variations, and modifications to the described aspects that would be known to those of ordinary skill in the pertinent art in light of the discussion herein.
Embodiments are provided throughout so that this disclosure is sufficiently thorough and fully conveys the scope of the disclosed embodiments to those who are skilled in the art. Numerous specific details are set forth, such as examples of specific aspects, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. Nevertheless, it will be apparent to those skilled in the art that certain specific disclosed details need not be employed, and that embodiments may be embodied in different forms. As such, the exemplary embodiments set forth should not be construed to limit the scope of the disclosure.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. For example, as used herein, the singular forms “a”, “an” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof.
The steps, processes, and operations described herein are thus not to be construed as necessarily requiring their respective performance in the particular order discussed or illustrated, unless specifically identified as a preferred or required order of performance. It is also to be understood that additional or alternative steps may be employed, in place of or in conjunction with the disclosed aspects.
Yet further, although the terms first, second, third, etc. may be used herein to describe various elements, steps or aspects, these elements, steps or aspects should not be limited by these terms. These terms may be only used to distinguish one element or aspect from another. Thus, terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, step, component, region, layer or section discussed below could be termed a second element, step, component, region, layer or section without departing from the teachings of the disclosure.
The non-limiting embodiments described herein are with respect to devices and methods for making the devices, where the devices are microelectromechanical systems (MEMS) transducers which are attached to a sidewall of a tapered horn antenna via a hole. The device and method for making the device may be modified for a variety of applications and uses while remaining within the spirit and scope of the claims. The embodiments and variations described herein, and/or shown in the drawings, are presented by way of example only and are not limiting as to the scope and spirit. The descriptions herein may be applicable to all embodiments of the device and the methods for making the devices.
Disclosed herein are implementations of devices and methods for side mounting of microelectromechanical systems (MEMS) transducers on tapered horn antennae. Although the description herein uses MEMS microphones for purposes of illustration, other MEMS transducers may be used without departing from the scope of the specification and the claims. Although the description herein is with respect to MEMS transducers, polyvinylidene difluoride (PVDF) sensors, piezoelectric sensors and the like may be used without departing from the scope of the specification and the claims.
Besides having no signal losses at low frequencies and improved sensitivity at higher frequencies, mounting the MEMS microphone 160 on the sidewall 190 of the tapered horn antenna 170 reduces the overall length of the device 150 by an amount equivalent to the total thickness of the MEMS microphone 160. This savings in real estate is a valuable commodity in thin film sensing devices such as, but not limited to, electrocardiogram (ECG) patches and the like. This mounting configuration may allow MEMS microphones to be used in low profile applications where real estate is significantly limited. The reduction in real estate used may be approximately 33% when compared to mounting configurations utilizing a throat area of the tapered horn antenna.
The method 1300 includes forming 1310 a hole in a sidewall of a tapered horn antenna. In an implementation, the hole is cylindrical having a diameter that is the same or slightly larger than the same as a diameter of an internal port opening of a MEMS microphone. In an implementation, the hole is tapered horn hole having a diameter at an attachment end that is the same or slightly larger than a diameter of an internal port opening of a MEMS microphone. The remaining end of the tapered horn hole having a diameter greater than the diameter at the attachment end. In an implementation, a connecting tube may be used to connect the MEMS microphone to the tapered horn antenna. In an implementation, the connecting tube may have a cylindrical shape. In an implementation, the connecting tube may have a tapered horn shape. At least one end of the connecting tube may be the same or slightly larger than a diameter of an internal port opening of a MEMS microphone. In an implementation, multiple holes may be formed into the sidewall of the horn to support a multiple MEMS device implementation to improve overall system signal to noise ratio (SNR).
The method 1300 includes aligning 1320 the internal port opening of the MEMS microphone with the hole. In an implementation, the internal port opening of the MEMS microphone is substantially aligned with the hole. In an implementation with multiple holes in the sidewall, each port opening of the MEMS microphone may be aligned to one of the multiple holes.
The method 1300 includes attaching 1330 the MEMS microphone to the tapered horn antenna. The attachment of the MEMS microphone to the tapered horn antenna may be accomplished using a number of techniques including pressing the MEMS microphone up against the horn sidewall with a soft compression gasket seal located at the interface and then secure the MEMS microphone into place by using epoxy or other known techniques. The soft compression gasket seal is illustrative and other devices and mechanisms that provide an air seal and reduce the mechanical coupling of vibrations that may occur between the tapered horn antenna and MEMS microphone may be used as known to those skilled in the art. In an implementation with multiple holes in the sidewall, each MEMS microphone may be attached to one of the multiple holes.
The construction and arrangement of the methods as shown in the various exemplary embodiments are illustrative only. Although only a few embodiments have been described in detail in this disclosure, many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials and components, colors, orientations, etc.). For example, the position of elements may be reversed or otherwise varied and the nature or number of discrete elements or positions may be altered or varied. Accordingly, all such modifications are intended to be included within the scope of the present disclosure. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions and arrangement of the exemplary embodiments without departing from the scope of the present disclosure.
Although the figures may show a specific order of method steps, the order of the steps may differ from what is depicted. Also, two or more steps may be performed concurrently or with partial concurrence. Such variation will depend on the software and hardware systems chosen and on designer choice. All such variations are within the scope of the disclosure. Likewise, software implementations could be accomplished with standard programming techniques with rule-based logic and other logic to accomplish the various connection steps, processing steps, comparison steps, and decision steps.
While the disclosure has been described in connection with certain embodiments, it is to be understood that the disclosure is not to be limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law.
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