Selected inventions by Chris Duffield:

Medical diagnostic device.  Disclosure made to Stanford University Office of Technology Licensing..

Pharmaceutical patent application:  Pending in 2002.  Drug enhancement, and nutraceutical applications.  No details to disclose publicly.

Multiscale medical measuring devices:  Mid 1990s.  Awarded US patent number 5400513.  Actually a family of designs.  In one set of devices, measuring scales at different magnification factors are available on one transparent sheet, sometimes a goniometer.  This would allow a doctor to choose the nearest scale for use on a particular medical image (X-ray, MRI, etc.).  Another set of devices had logarithmic functions built in like a slide rule, and allowed for the measurement of objects (such as blood vessels in angiograms) in images of arbitrary magnification, when another object of known size appears in the same image.

Neuroscience electrode fabrication process:  Early 1990s.  One of my major contributions to science.  Around 3 am at a neuroscience lab at the University of Arizona, I found that very fine kapton-coated wires, twisted together and pulled straight, somehow stuck together to make a stiffer, stronger, straighter assembly when heated with a hot air gun.  (The previous method was to dip them in glue.)  "Tetrodes" (4-wire electrodes) made by this technique are now used to probe the brains of rats and other animals in many different neuroscience labs.

Vortenna ™ Vortex antennas:  Late 1980s.  Wire or PC board antennas that look like the Star of David, with proper weave and twist.  Anecdotally and reportedly in the lab, these interacted with human bioenergy, stimulating and balancing chakras and acupuncture points.  Production version was a printed circuit disk, with traces as wires, and weave done by plated-through holes.  Two sizes were made, 1.5 and 3.5 inches diameter, in bare copper or with gold plating.  The first ones were on clear material with blue soldermask.  Later ones were on blue material with clear soldermask, showing the traces much better.  Many people experimented with these disks, hooking them up to electronic devices, etc.  And many people reported wonderful anecdotal results.  I also built some large ones to see if it would create the feeling of a natural vortex or a temple.  I never succeeded in demonstrating effects in the laboratory, and I took Vortenna disks quietly out of most markets by 1992.

Tesla turbine jet engines:  Late 1980s.  Inspired by Nikola Tesla's patents (around 1912) for simple disk turbines, pumps, and compressors, I got the idea for making a gas turbine engine using them.  And I had a lot of ideas for improving performance and varying the disk spacing dynamically,   It turned out that other people had come up with similar ideas and had patented them.  But this was fun to think about, and good practice.

Meditation rest:  Mid 1980s?  An extremely comfortable meditation rest made with simple materials and methods.  It took the form of a T bar, with the user resting arms on the two top ends of the T.  My version of this ancient device had a top bar that was form-fitting, springy, and padded with foam and a fake fleece cover.   The vertical member was a clever construction made of a length of PVC pipe, a short machine screw, and a wooden dowel that had a beautiful ratchet-like pattern cut in it to engage with the screw and allow for quick and easy height adjustment.  The group that I was (and am still) involved with suddenly stopped using them, right around the time that my production machine burned up.

Webbed swimming/surfing gloves:  Early 1980s?  I saw these first in a dream...  I was surfing and looked down at my hands to see gloves with webs between fingers to give me more power per stroke.  I made some prototypes, but never went into production.  A few years later someone else did.  But I haven't seen them on the market for years.

Running shoes:  Early 1980s?  Normal shoes today all have flat bottoms, with minor improvements like tread patterns and cushioned insoles.  I found that if the heel, in particular,  is rounded to approximate the shape of the real foot's heel, a shoe has great advantages.  No longer is there a long lever arm and pivot edge to force the foot to either land straight up or on its side (causing ankle sprain).  The foot can land or be held at any angle from vertical to sideways, and remain there stably.  This is very comfortable for running, walking, and even sitting.  It helps if the rest of the sole has rounded edges, too.  About 8 years after I had this idea and built some prototypes, someone else actually patented it.  But it still hasn't entered the market.  I also played with very comfortable stretchy shoe uppers.  I made shoe prototypes out of white athletic socks with form fitting molded rounded soles.  Years later, Nike came out with running shoes that consisted of elastic mesh with light soles, with a minimum of straps to hold them in place.  They didn't do well in the running market, and now survive mainly as mesh river shoes.

My ideal shoes would have contoured insoles sculpted like Birkenstocks, very lightweight midsoles with air cushioning all the way from front to back,  very lightweight outer sole, with traction tread, rounded bottom shape that looks like a natural foot, only larger, especially in the heel area, and a lightweight mesh upper made like water shoes, for air circulation, with a few straps similar to Tevas, only lighter,  to hold the shoes in place.  Ideally these would come in a white version for desert running, and an all-black version, without contrasting color logos or decoration, for use as comfortable athletic formalwear, suitable for jogging, running to catch a plane, and business meetings.

Yogurt incubator box:  Late 1970s.  Hot air rises.  So I built boxes out of styrofoam (and covered with attractive Contact (R) paper) that were like square bell jars, with a square base, and an inverted box that would keep a glass jar of warm milk plus yogurt culture at a warm temperature overnight.  The market was flooded with yogurt makers, so I didn't get very far.

Geodesic solar reflector:  Mid 1970s.  Corrugated cardboard construction made of triangles with precise measurements that fold into a segment of a sphere.  The triangles were covered with aluminum foil.  It could boil water and cook meat.