A flexible printed circuit, comprising: a main sub-circuit board, comprising a first substrate, and a first bridge end, a second bridge end, a first wiring portion, and a second wiring portion on the first substrate, wherein the first wiring portion and the second wiring portion are spaced apart from each other and are electrically connected to the first bridge end and the second bridge end, respectively; and a bridge sub-circuit board, comprising a second substrate, and a third bridge end, a fourth bridge end, and a third wiring portion for a first functional wiring line on the second substrate, wherein the third bridge end and the fourth bridge end are electrically connected by the third wiring portion, wherein the first substrate and the second substrate are not in direct contact, and the bridge sub-circuit board is configured to be mounted on the main sub-circuit board by electrically connecting the third bridge end and the fourth bridge end to the first bridge end and the second bridge end, respectively; the flexible printed circuit further comprises a first control circuit combination structure, the first control circuit combination structure is on the main sub-circuit board and is electrically connected to the first wiring portion, or the first control circuit combination structure is on the bridge sub-circuit board and is electrically connected to the third wiring portion; the first control circuit combination structure is configured to provide a first electrical signal to the first functional wiring line or receive a first electrical signal from the first functional wiring line; the main sub-circuit board further comprises a second functional wiring line, the second functional wiring line is electrically connected to the first control circuit combination structure on the main sub-circuit board, and the first control circuit combination structure is further configured to provide a second electrical signal to the second functional wiring line or receive a second electrical signal from the second functional wiring line; characterized in that the main sub-circuit board further comprises a third functional wiring line, and the third functional wiring line is between the first wiring portion and the second wiring portion, and crosses the bridge sub-circuit board mounted on the main sub-circuit board; the first wiring portion, the second wiring portion, and the third functional wiring line are routed in a same direction. a main sub-circuit board, comprising a first substrate, and a first bridge end, a second bridge end, a first wiring portion, and a second wiring portion on the first substrate, wherein the first wiring portion and the second wiring portion are spaced apart from each other and are electrically connected to the first bridge end and the second bridge end, respectively; and a bridge sub-circuit board, comprising a second substrate, and a third bridge end, a fourth bridge end, and a third wiring portion for a first functional wiring line on the second substrate, wherein the third bridge end and the fourth bridge end are electrically connected by the third wiring portion, wherein the first substrate and the second substrate are not in direct contact, and the bridge sub-circuit board is configured to be mounted on the main sub-circuit board by electrically connecting the third bridge end and the fourth bridge end to the first bridge end and the second bridge end, respectively; the flexible printed circuit further comprises a first control circuit combination structure, the first control circuit combination structure is on the main sub-circuit board and is electrically connected to the first wiring portion, or the first control circuit combination structure is on the bridge sub-circuit board and is electrically connected to the third wiring portion; the first control circuit combination structure is configured to provide a first electrical signal to the first functional wiring line or receive a first electrical signal from the first functional wiring line; the main sub-circuit board further comprises a second functional wiring line, the second functional wiring line is electrically connected to the first control circuit combination structure on the main sub-circuit board, and the first control circuit combination structure is further configured to provide a second electrical signal to the second functional wiring line or receive a second electrical signal from the second functional wiring line; characterized in that the main sub-circuit board further comprises a third functional wiring line, and the third functional wiring line is between the first wiring portion and the second wiring portion, and crosses the bridge sub-circuit board mounted on the main sub-circuit board; the first wiring portion, the second wiring portion, and the third functional wiring line are routed in a same direction.