Thomas Edward Pollard

US Patent:

49159178, Apr 10, 1990

Filed:

Feb 19, 1987

Appl. No.:

7/016570

Inventors:

Thomas D. Pollard - Baltimore MD
Ueli Aebi - Bottmingen, CH

Assignee:

The Johns Hopkins University - Baltimore MD

International Classification:

B01J 1908

US Classification:

42218605

Abstract:

A glow discharge unit suitable for making surfaces such as carbon-coated electron microscopy grids and glass cover slips hydrophilic. The use of a vacuum leak detector (Tesla coil) in place of a conventional high voltage power supply and a small plastic desiccator for the vacuum chamber make the unit very inexpensive. Due to the small volume of the chamber and the simplicity of the unit, the whole glow discharge process can be carried out in only 2 to 3 min. , a time considerably shorter than that required for conventional vacuum evaporators. The hydrophilic surfaces thus obtained improve adsorption of particles by several orders of magnitude in preparation for negative staining, freeze-drying and other procedures.

US Patent:

20210143792, May 13, 2021

Filed:

May 28, 2019

Appl. No.:

17/256985

Inventors:

- Munchen, DE
Thomas Bain POLLARD - Longwood FL, US

International Classification:

H03H 9/17
H03H 9/02
H03H 9/13
H03H 9/56

Abstract:

A BAW resonator is provided wherein the top electrode (TE) has an outer flap (OF). The flap extends away from the active resonator region (AR) and has a projecting section that runs at a level above the piezoelectric layer (PL) that is higher than the level of the top electrode at any of the inwardly located areas enclosed by the outer flap. The higher level is formed by an intermediate step-forming material (SM) arranged between piezoelectric layer and top electrode in the outer flap. The step forming material comprises a structured layer of an acoustic impedance that is low w.r.t. the impedance of the top electrode and the piezoelectric layer.

US Patent:

20210013862, Jan 14, 2021

Filed:

Feb 4, 2019

Appl. No.:

16/977753

Inventors:

- Munchen, DE
Yoshikazu KIHARA - Honjo, JP
Thomas POLLARD - Longwood FL, US

International Classification:

H03H 9/02
H03H 3/08
H03H 9/145
H03H 9/25
H01L 41/08
H01L 41/319

Abstract:

A layer system especially for forming SAW devices thereon is proposed comprising a monocrystalline sapphire substrate having a first surface and a crystalline piezoelectric layer comprising MN, deposited onto the first surface, and having a second surface. As a first surface a crystallographic R-plane of sapphire is used enabling an orientation of c-axis of the piezoelectric layer parallel to the first and second surfaces.

US Patent:

20190089326, Mar 21, 2019

Filed:

Sep 15, 2017

Appl. No.:

15/706654

Inventors:

- San Diego CA, US
Thomas Bain Pollard - Longwood FL, US
Brian Hal Fisher - Orlando FL, US
Janardan Nath - Orlando FL, US

International Classification:

H03H 9/02
H03H 3/02
H03H 9/13
H03H 9/54
H03H 9/56

Abstract:

Acoustic resonators with enhanced boundary conditions are disclosed. In an example aspect, a resonator includes a volume of piezoelectric material including an upper surface and a lower surface. The resonator also includes a bottom electrode extending along a portion of the lower surface of the volume of piezoelectric material. The resonator further includes a multi-layered top electrode extending along a portion of the upper surface of the volume of piezoelectric material. The multi-layered top electrode includes an active region including an interface layer of a first thickness, where the active region overlaps a portion of the bottom electrode. The multi-layered top electrode also includes a frame region including the interface layer of a second thickness, where the second thickness is greater than the first thickness. The multi-layered top electrode further includes an outer region including the interface layer of a third thickness, where the third thickness is less than the second thickness.

US Patent:

20190089332, Mar 21, 2019

Filed:

Sep 18, 2017

Appl. No.:

15/707458

Inventors:

- San Diego CA, US
Thomas Bain Pollard - Longwood FL, US
Brian Hal Fisher - Orlando FL, US
Janardan Nath - Orlando FL, US

International Classification:

H03H 9/54
H03H 9/17
H01L 41/314
H03H 9/13

Abstract:

Example implementations of a bulk acoustic wave resonator with an optimized outer perimeter are disclosed. In an example aspect, a resonator includes a truncated-ellipsoid-shaped active region. The active region includes an outer electrode disposed as a first layer of the active region. The active layer also includes a piezoelectric layer disposed as a second layer of the active region with the piezoelectric layer disposed interior to the outer electrode. The active layer further includes an inner electrode disposed as a third layer of the active region with the inner electrode disposed interior to the piezoelectric layer.