Patents by Inventor Jae Yoong Cho
Jae Yoong Cho has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Publication number: 20240110789Abstract: Disclosed herein are vibratory gyroscopes comprising hollow shell resonators and methods of fabricating thereof. Specifically, a vibratory gyroscope comprises a support substrate comprising a substrate primary surface and a resonator support surface, substantially perpendicular to the substrate primary surface. The gyroscope also comprises a hollow shell resonator comprising a resonator inner surface and a resonator outer surface such that the resonator inner surface defines a recessed region with a recessed region opening facing the substrate primary surface. At least one of the inner or outer resonator surfaces is attached to the resonator support surface of the support substrate adjacent to the inner edge surface of the resonator. The inner edge surface can be formed by a hollow stem with or without opening through this surface. Furthermore, the resonator support surface can be a continuous cylindrical surface or a segmented surface.Type: ApplicationFiled: December 4, 2023Publication date: April 4, 2024Applicant: Enertia Microsystems Inc.Inventors: Jae Yoong Cho, Khalil Najafi
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Publication number: 20240019249Abstract: Three-dimensional (3D) micro-scale shells are presented with selectively removed regions/openings and which can be used in sensors and actuators, including gyroscopes. Example shells consisting of a suspended ring-shaped resonator that is supported using multiple beams that are not in the plane of the ring and are attached to a support post can be formed. Shells with various sizes and geometries of selectively removed regions and openings allow the creation of micro electromechanical systems (MEMS) sensors and actuators with a wide range of engineered mechanical and electrical properties. These shells can be used to form stacked 3D structures for various types of MEMS sensor and actuator devices, such as resonant gyroscopes, with sense and drive electrodes that conform to the curved profile of the resonant shell using for gyroscopes. 3D shells formed from a starting parent substrate are released and separated from their parent substrate using a number of techniques.Type: ApplicationFiled: June 13, 2023Publication date: January 18, 2024Applicant: THE REGENTS OF THE UNIVERSITY OF MICHIGANInventors: Khalil NAJAFI, Sajal SINGH, Jae Yoong CHO
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Patent number: 11874112Abstract: Disclosed herein are vibratory gyroscopes comprising hollow shell resonators and methods of fabricating thereof. Specifically, a vibratory gyroscope comprises a support substrate comprising a substrate primary surface and a resonator support surface, substantially perpendicular to the substrate primary surface. The gyroscope also comprises a hollow shell resonator comprising a resonator inner surface and a resonator outer surface such that the resonator inner surface defines a recessed region with a recessed region opening facing the substrate primary surface. At least one of the inner or outer resonator surfaces is attached to the resonator support surface of the support substrate adjacent to the inner edge surface of the resonator. The inner edge surface can be formed by a hollow stem with or without opening through this surface. Furthermore, the resonator support surface can be a continuous cylindrical surface or a segmented surface.Type: GrantFiled: October 4, 2023Date of Patent: January 16, 2024Assignee: Enertia Microsystems Inc.Inventors: Jae Yoong Cho, Khalil Najafi
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Patent number: 11703331Abstract: Three-dimensional (3D) micro-scale shells are presented with openings of various sizes and geometries on the surface. The shell consist of a suspended ring-shaped resonator, multiple support beams, a support post, and a cap region that connects the support beams to the support post. Shells with openings of various sizes and geometries allow the creation of micro electromechanical systems (MEMS) sensors and actuators with a wide range of engineered mechanical and electrical properties. The openings on the shell surface can, for example, control the mechanical quality factor (Q) and resonance frequencies of the shell when the shell is used as a suspended proof mass of a mechanical resonator of a vibratory gyroscope. The shells can also serve as mechanical supporting layers and/or an electrode connection layer for MEMS actuators and sensors that use 3D shells as proof masses.Type: GrantFiled: March 18, 2021Date of Patent: July 18, 2023Assignee: THE REGENTS OF THE UNIVERSITY OF MICHIGANInventors: Khalil Najafi, Sajal Singh, Jae Yoong Cho
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Patent number: 11548805Abstract: Gyroscopes are sensors that measure angular rate and angular orientation. A three-dimensional fused silica micro shell rate-integrating gyroscope is presented. One aspect of the gyroscope includes the use of optical sensors to detect motion of the resonator. The proposed gyroscope is attractive because it achieves several magnitudes higher accuracy as well as high vibration and shock insensitivity from a novel resonator design as well as other unique manufacturing processes.Type: GrantFiled: December 23, 2019Date of Patent: January 10, 2023Assignee: The Regents of the University of MichiganInventors: Khalil Najafi, Jae Yoong Cho, Ali Darvishian, Guohong He, Behrouz Shiari, Tal Nagourney
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Patent number: 11346668Abstract: A method of adjusting an operating parameter of a miniature electromechanical resonator comprises measuring angular coordinates of first and second principal stiffness axes of first and second wine-glass mode of the miniature electromechanical resonator, respectively; determining first and second wine-glass mode frequencies of the resonator being resonant frequencies of the first and second principal stiffness axes, respectively; calculating one or more locations on the resonator for machining to reduce a difference between the first and second wine-glass mode frequencies; and machining the one or more locations on the resonator to reduce the difference between the first and second wine-glass mode frequencies.Type: GrantFiled: December 11, 2020Date of Patent: May 31, 2022Assignee: ENERTIA MICROSYSTEMS INC.Inventor: Jae Yoong Cho
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Publication number: 20220090917Abstract: Three-dimensional (3D) micro-scale shells are presented with openings of various sizes and geometries on the surface. The shell consist of a suspended ring-shaped resonator, multiple support beams, a support post, and a cap region that connects the support beams to the support post. Shells with openings of various sizes and geometries allow the creation of micro electromechanical systems (MEMS) sensors and actuators with a wide range of engineered mechanical and electrical properties. The openings on the shell surface can, for example, control the mechanical quality factor (Q) and resonance frequencies of the shell when the shell is used as a suspended proof mass of a mechanical resonator of a vibratory gyroscope. The shells can also serve as mechanical supporting layers and/or an electrode connection layer for MEMS actuators and sensors that use 3D shells as proof masses.Type: ApplicationFiled: March 18, 2021Publication date: March 24, 2022Inventors: Khalil NAJAFI, Sajal SINGH, Jae Yoong CHO
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Publication number: 20210180951Abstract: A method of adjusting an operating parameter of a miniature electromechanical resonator comprises measuring angular coordinates of first and second principal stiffness axes of first and second wine-glass mode of the miniature electromechanical resonator, respectively; determining first and second wine-glass mode frequencies of the resonator being resonant frequencies of the first and second principal stiffness axes, respectively; calculating one or more locations on the resonator for machining to reduce a difference between the first and second wine-glass mode frequencies; and machining the one or more locations on the resonator to reduce the difference between the first and second wine-glass mode frequencies.Type: ApplicationFiled: December 11, 2020Publication date: June 17, 2021Inventor: Jae Yoong Cho
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Patent number: 11027479Abstract: Methods for fabricating three-dimensional microstructures are provided. The method includes disposing a reflow material on a mold, heating the reflow material, and creating a pressure gradient across the reflow material to reflow the material towards a bottom surface of the mold. The mold includes a molding region, a boundary region, and a thermal-isolating region disposed therebetween. The molding region includes a cavity and a projection projecting upwards from a bottom surface of the cavity. The thermal-isolating region includes at least one pocket formed adjacent to and along a perimeter of the cavity of the molding region. During heating, the temperature of the molding region is higher than that of the boundary region and the thermal-isolating region controls the thermal conductivity and mass therebetween. The material reflows towards the bottom surface of the cavity and the protrusion helps shapes the reflow material to form a substantially symmetrical three-dimensional microstructure.Type: GrantFiled: September 21, 2017Date of Patent: June 8, 2021Assignee: THE REGENTS OF THE UNIVERSITY OF MICHIGANInventors: Khalil Najafi, Jae Yoong Cho
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Publication number: 20200277215Abstract: Gyroscopes are sensors that measure angular rate and angular orientation. A three-dimensional fused silica micro shell rate-integrating gyroscope is presented. One aspect of the gyroscope includes the use of optical sensors to detect motion of the resonator. The proposed gyroscope is attractive because it achieves several magnitudes higher accuracy as well as high vibration and shock insensitivity from a novel resonator design as well as other unique manufacturing processes.Type: ApplicationFiled: December 23, 2019Publication date: September 3, 2020Inventors: Khalil NAJAFI, Jae Yoong CHO, Ali DARVISHIAN, Guohong HE, Behrouz SHIARI, Tal NAGOURNEY
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Patent number: 10730748Abstract: A method for fabricating three-dimensional microstructures is presented. The method includes: disposing a substantially planar reflow material between two molds; heating the reflow material while the reflow material is disposed between the two molds; and reflowing the reflow material towards the bottom surface of one of the molds by creating a pressure gradient across the reflow material. At least one of molds includes geometrics features that help to shape the reflow material and thereby form a complex three-dimensional microstructure.Type: GrantFiled: September 20, 2017Date of Patent: August 4, 2020Assignee: THE REGENTS OF THE UNIVERSITY OF MICHIGANInventors: Khalil Najafi, Tal Nagourney, Jae Yoong Cho
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Publication number: 20200216311Abstract: A method for fabricating three-dimensional microstructures is presented. The method includes: disposing a substantially planar reflow material between two molds; heating the reflow material while the reflow material is disposed between the two molds; and reflowing the reflow material towards the bottom surface of one of the molds by creating a pressure gradient across the reflow material. At least one of molds includes geometrics features that help to shape the reflow material and thereby form a complex three-dimensional microstructure.Type: ApplicationFiled: September 20, 2017Publication date: July 9, 2020Inventors: Khalil NAJAFI, Tal NAGOURNEY, Jae Yoong CHO
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Patent number: 10612925Abstract: Three-dimensional microstructure devices having substantially perfect alignment and leveling of a three-dimensional microstructure with respect to a substrate having a plurality of discrete electrodes and relating fabricating methods are disclosed. Seed layers are deposited onto the discrete electrodes of the substrate, and the three-dimensional microstructure is bonded adjacent to the seed layers. A substantially uniform sacrificial layer is deposited onto exposed surfaces of the three-dimensional microstructure. A plurality of first gaps exists between the seed layers and corresponding regions of the sacrificial layer. Conductive layers are deposited to fill the first gaps. The sacrificial layer is dissolved to create a second plurality of gaps between the conductive layers and the corresponding regions of the three-dimensional microstructure. The second gaps are substantially uniform.Type: GrantFiled: February 28, 2017Date of Patent: April 7, 2020Assignee: THE REGENTS OF THE UNIVERSITY OF MICHIGANInventors: Khalil Najafi, Jae Yoong Cho
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Patent number: 10532943Abstract: Gyroscopes are sensors that measure angular rate and angular orientation. A three-dimensional fused silica micro shell rate-integrating gyroscope is presented. One aspect of the gyroscope includes the use of optical sensors to detect motion of the resonator. The proposed gyroscope is attractive because it achieves several magnitudes higher accuracy as well as high vibration and shock insensitivity from a novel resonator design as well as other unique manufacturing processes.Type: GrantFiled: February 28, 2017Date of Patent: January 14, 2020Assignee: THE REGENTS OF THE UNIVERSITY OF MICHIGANInventors: Khalil Najafi, Jae Yoong Cho, Ali Darvishian, Guohong He, Behrouz Shiari, Tal Nagourney
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Publication number: 20190094024Abstract: Three-dimensional microstructure devices having substantially perfect alignment and leveling of a three-dimensional microstructure with respect to a substrate having a plurality of discrete electrodes and relating fabricating methods are disclosed. Seed layers are deposited onto the discrete electrodes of the substrate, and the three-dimensional microstructure is bonded adjacent to the seed layers. A substantially uniform sacrificial layer is deposited onto exposed surfaces of the three-dimensional microstructure. A plurality of first gaps exists between the seed layers and corresponding regions of the sacrificial layer. Conductive layers are deposited to fill the first gaps. The sacrificial layer is dissolved to create a second plurality of gaps between the conductive layers and the corresponding regions of the three-dimensional microstructure. The second gaps are substantially uniform.Type: ApplicationFiled: February 28, 2017Publication date: March 28, 2019Applicant: The Regents of The University of MichiganInventors: Khalil NAJAFI, Jae Yoong CHO
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Publication number: 20180079129Abstract: Methods for fabricating three-dimensional microstructures are provided. The method includes disposing a reflow material on a mold, heating the reflow material, and creating a pressure gradient across the reflow material to reflow the material towards a bottom surface of the mold. The mold includes a molding region, a boundary region, and a thermal-isolating region disposed therebetween. The molding region includes a cavity and a projection projecting upwards from a bottom surface of the cavity. The thermal-isolating region includes at least one pocket formed adjacent to and along a perimeter of the cavity of the molding region. During heating, the temperature of the molding region is higher than that of the boundary region and the thermal-isolating region controls the thermal conductivity and mass therebetween. The material reflows towards the bottom surface of the cavity and the protrusion helps shapes the reflow material to form a substantially symmetrical three-dimensional microstructure.Type: ApplicationFiled: September 21, 2017Publication date: March 22, 2018Inventors: Khalil NAJAFI, Jae Yoong CHO
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Patent number: 9796586Abstract: A method for fabricating three-dimensional microstructures is presented. The method includes: disposing a substantially planar reflow material between two molds; heating the reflow material while the reflow material is disposed between the two molds; and reflowing the reflow material towards the bottom surface of one of the molds by creating a pressure gradient across the reflow material. At least one of molds includes geometrics features that help to shape the reflow material and thereby form a complex three-dimensional microstructure.Type: GrantFiled: December 31, 2015Date of Patent: October 24, 2017Assignee: THE REGENTS OF THE UNIVERSITY OF MICHIGANInventors: Khalil Najafi, Tal Nagourney, Jae Yoong Cho
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Patent number: 9778039Abstract: A microsystem includes a base layer formed from an electrical insulating material. The base layer has an inner surface defining a cavity and an external surface opposed to the inner surface, and in direct communication with an environment. A cap layer and a microelectromechanical (MEMS) device layer are formed from electrical insulating material or an other electrical insulating material. The cap has an inner surface defining a cavity, and an external surface opposed to the inner surface, and in direct communication with the environment. A MEMS device on/in the MEMS device layer is disposed between the base and the cap. Respective adjacent portions of the base, the cap and the device substrate are bonded to define an enclosed space. The enclosed space at least partially includes the base cavity or the cap cavity. At least a portion of a MEMS device on the device layer is in the enclosed space.Type: GrantFiled: October 31, 2012Date of Patent: October 3, 2017Assignee: The Regents of the University of MichiganInventors: Khalil Najafi, Rebecca L. Peterson, Jae Yoong Cho, Zongliang Cao, Guohong He, Jeffrey Gregory, Yi Yuan
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Publication number: 20170248422Abstract: Gyroscopes are sensors that measure angular rate and angular orientation. A three-dimensional fused silica micro shell rate-integrating gyroscope is presented. One aspect of the gyroscope includes the use of optical sensors to detect motion of the resonator. The proposed gyroscope is attractive because it achieves several magnitudes higher accuracy as well as high vibration and shock insensitivity from a novel resonator design as well as other unique manufacturing processes.Type: ApplicationFiled: February 28, 2017Publication date: August 31, 2017Inventors: Khalil NAJAFI, Jae Yoong CHO, Ali DARVISHIAN, Guohong HE, Behrouz SHIARI, Tal NAGOURNEY
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Patent number: 9494425Abstract: A gyroscope having a mechanical resonator, a plurality of electrodes located around the resonator, and a thin gap being located between the resonator and the plurality of electrodes. The resonator is axi-symmetric and may be at least partially toroidal in shape or composed of concentric rings. Piezoelectric electrodes or transduction may be used to drive or detect displacements of the resonator. The resonator may be fabricated using a fused silica flowing process.Type: GrantFiled: May 25, 2012Date of Patent: November 15, 2016Assignee: The Regents of the University of MichiganInventors: Khalil Najafi, Jae Yoong Cho