Correlated Magnetics: Strength and Safety

A conventional magnet can have a strong magnetic field that can be quite dangerous because a nearby magnet or metallic object may be propelled towards the magnet or vice versa. Moreover, such strong fields can adversely impact credit cards, cell phones, pacemakers, hard drives, etc. In stark contrast, correlated magnetic structures have magnetic fields with much higher near-field density and much lower far-field density than conventional magnets. As such, very strong correlated magnetic structures can be created that produce stronger peak attractive force when attached to metal or to another correlated magnetic structure yet have attractive forces that rapidly diminish as they are separated from the metal or other correlated magnetic structure. This rapid reduction in attractive force during separation results in the correlated magnetic structures being stronger yet safer than conventional magnets. This stronger yet safer behavior is attributed to a “shortest path effect” from which correlated magnetic structures benefit as a direct result of how they are constructed (i.e., programmed). 

Each correlated magnetic structure comprises an array of magnetic sources, or “maxels” in analog to “pixels”, having polarities that vary in accordance with a defined program (or code). A typically maxel will have at least one adjacent source with the opposite polarity. A positive (or north) polarity maxel will be surrounded by some combination of other sources where at least one adjacent magnetic source is a negative (or south) polarity maxel.   Similarly, a negative (or south) polarity magnetic source will be surrounded by some combination of other sources where at least one adjacent magnetic source is a positive (or north) polarity larger magnetic source. Two or more adjacent magnetic sources with the same polarity essentially behave as one magnetic source.  As such, a group of two or more adjacent magnetic sources with the same polarity will have at least one adjacent magnetic source having the opposite polarity or an adjacent group of magnetic sources with the opposite polarity. Unlike conventional magnets where significant magnetism emanates into the far field, each combination of opposite polarity magnetic sources of correlated magnetic structures benefits from the shortest path effect. This causes the magnetic field density to be concentrated in the near field such as depicted in Fig. 1 rather than being dispersed into the far field. 

Fig.1. Adjacent Magnets Having Same Polarity Orientation Vs. Adjacent Magnets Having Opposite Polarity Orientation

The extent to which a correlated magnetic structure is stronger yet safer than a conventional magnet is largely a function of the code density used to program the structure. The code density corresponds to how many magnetic sources are present in the structure and, for those sources, the number of adjacent opposite polarity sources and thus the extent that the shortest path effect causes the magnetic field of the structure to be concentrated into the near field. Other factors include the thickness of the magnetizable material (e.g., Neodymium Iron Boron) and the extent of magnetization of each of the magnetic sources. Two correlated magnetic structures of 19 discrete magnets have been shown to produce twice the tensile force and twice the shear force as 19 of the same type of discrete magnets with the same polarity orientation because of their near field density concentration as shown in Fig. 2. 

Fig.2. Cross-Sections of the Magnetic Fields Emanating From Correlated Magnetic Structure (top) and From a Structure Having
Magnetic Sources All Having the Same Polarity Orientation (bottom) as Seen Through Magnetic Viewing Film

Moreover, the stronger attractive force of the correlated magnetic structures diminishes rapidly as they are separated such that the distance at which two such correlated magnetic structures will engage is far less than the engagement distance of two conventional, identically constructed magnets having a much weaker peak attractive force. A comparison of the attractive force vs. separation distance for the two Coded Magnets and two conventional magnets is provided in Fig. 3.

Fig.3. Attractive Force vs. Separation Distance of Two Coded Magnets and Two Conventional Magnets

A comparison of a Coded Magnet and iron versus a conventional magnet and iron is provided in Fig. 4.

Fig.4. Attractive Force vs. Separation Distance of Two Coded Magnets and Two Conventional Magnets

Thus, the varying of the polarities of the magnetic sources of correlated magnetic structures causes them to benefit from the shortest path effect, enabling them to be much stronger, yet much safer, than conventional magnets.