Membrane circuit board and manufacturing method thereof

A membrane circuit board, comprising:

• a first film substrate, wherein a first circuit layer is installed on the first film substrate;
• a second film substrate opposed to the first film substrate, wherein a second circuit layer is installed on the second film substrate;
• an insulating spacer substrate arranged between the first film substrate and the second film substrate, wherein the first circuit layer is arranged between the first film substrate and the insulating spacer substrate, and the second circuit layer is arranged between the second film substrate and the insulating spacer substrate;
• and
• a waterproof structure comprising a first welding layer and a second welding layer, wherein the first welding layer is arranged between the first film substrate and the insulating spacer substrate, and the first welding layer is arranged around the first circuit layer, wherein the second welding layer is arranged between the second film substrate and the insulating spacer substrate, and the second welding layer is arranged around the second circuit layer,
• wherein the first film substrate has a first positioning opening, the insulating spacer substrate has a second positioning opening, and the second film substrate has a third positioning opening, wherein the first positioning opening, the second positioning opening and the third positioning opening are aligned with each other,
• wherein the first welding layer comprises a first welding part and a second welding part, and the second welding layer comprises a third welding part and a fourth welding part, wherein the first welding part is arranged around the first circuit layer and the second welding part, and the second welding part is arranged around a region between the first positioning opening and the second positioning opening, wherein the third welding part is arranged around the second circuit layer and the fourth welding part, and the fourth welding part is arranged around a region between the second positioning opening and the third positioning opening,
• wherein the first welding layer further comprises a fifth welding part, and the second welding layer further comprises a sixth welding part, wherein the fifth welding part is arranged between the first circuit layer and the first welding part, the fifth welding part is arranged around the first circuit layer and the second welding part, the sixth welding part is arranged between the second circuit layer and the third welding part, and the sixth welding part is arranged around the second circuit layer and the fourth welding part.