David Grewell. Laser Beam Shaping Using Liquid Crystals. US Patent 6,867,388.

David Grewell, Justin Bickford, Donald Lovett, Paul Rooney. Light Guide for Laser Welding. US Patent 6,528,755.

David Grewell, Donald Lovett. Transparent Pressure Bladder. US Patent 6,486,433.

David Grewell. Distance Mode Control for Laser Welding. US Patent 6,329,629.

David Grewell. Laser Diode Array. US Patent 6,205,016.

Don Lovett, David Grewell. Welding Method and Apparatus. US Patent 6,064,798.

Don Lovett, David Grewell. Welding Method and Apparatus. US Patent 5,949,959.

David Grewell. Simultaneous Amplitude and Force Profiling During Ultrasonic Welding of Thermoplastic Workpieces. US Patent 5,855,706.

Jeffrey Frantz, David Grewell. Method for Processing Workpieces by Ultrasonic Energy. US Patent 5,846,377.

David Grewell. Method of Determining the Collapse of Plastic Parts. US Patent 5,788,791.

David Grewell. Welding System and Method of Setting Welding Machine Parameters. US Patent 5,772,814.

Robert Grimm, David Grewell, Mark St. John. Thermoplastic Welding. US Patent 5,313,034.

Jeffrey Frantz, David Grewell. Method and Apparatus for Processing Workpieces by Ultrasonic Energy. US Patent 5,658,408.