Direct-ink-writing method for printing strain gauge array circuit

A novel direct-ink-writing (DIW) method for printing a strain gauge array circuit, the method comprising:

• forming a first insulating layer by DIW printing on a planar substrate using an insulating material;
• forming m parallel spaced first silver lines by DIW printing on the insulating layer using conductive silver paste to form a first circuit layer, wherein one end of each first silver line comprises an electrode lead-out end;
• forming a second insulating layer by DIW printing on other regions of the first circuit layer except the respective electrode lead-out ends using the insulating material, wherein n through holes are respectively formed in a position of the second insulating layer that directly faces each first silver line at an interval, and all the through holes form an m*n row and column structure;
• the respective electrode lead-out ends of the first silver lines and the first silver lines at the respective through holes are all exposed with respect to the second insulating layer;
• printing n parallel spaced second silver lines on the second insulating layer using conductive silver paste to form a second circuit layer, wherein each second silver line respectively comprises a main line and m branches connected thereto, and the main line of the second silver line is perpendicular to the first silver line and has one end including an electrode lead-out end;
• forming m*n strain gauge head electrodes, m*n strain gauge tail electrodes, and m*n connecting wires by DIW printing using conductive carbon paste to form a functional layer, wherein one strain gauge head electrode is respectively printed at each through hole of the second insulating layer;
• the strain gauge head electrodes are communicated to the first silver lines on the first circuit layer through the through holes on the second insulating layer;
• one strain gauge tail electrode is printed at the tail end of the branch of each second silver line on the second circuit layer;
• each strain gauge head electrode corresponds to one strain gauge tail electrode and is connected to the strain gauge tail electrode through a connecting wire;
• printing and forming a third insulating layer using an insulating material to complete encapsulation, wherein the third insulating layer covers other regions except the electrode lead-out ends of the first circuit layer, the electrode lead-out ends of the second circuit layer, and the strain gauge head electrodes and the strain gauge tail electrodes on the functional layer.