A controller, comprising: at least one flexible printed circuit board (100; 300), comprising: an annular main board (110; 310); a plurality of branches (120; 320a, 320b) connected with and surrounding the annular main board (110; 310) and each of the branches (120; 320a, 320b) comprising an extension portion (122; 322a, 322b) and a bonding portion (124; 324a, 324b), wherein the extension portion (122; 322a, 322b) connects the bonding portion (124; 324a, 324b) with the annular main board (110; 310) and wherein a width of each of the bonding portions (124; 324a, 324b) is greater than a width of the corresponding extension portion (122; 322a, 322b), an electronic component (52; 54) disposed on the bonding portion (124; 324a, 324b) of each of the branches (120; 320a; 320b), wherein the electronic component (52,54) is electrically connected with connection lines on the corresponding branch (120; 320a; 320b); and at least one supporting holder (200; 400) supporting the at least one flexible printed circuit board (100; 300), respectively, the at least one supporting holder (200,400) comprising: an annular base (210; 410); two wing structures (220a, 220b; 420a, 420b) extending outward from the annular base (210; 410); and a plurality of mounting portions (230; 430) located on the annular base (210; 410) and the wing structures (220a, 220b; 420a, 420b), wherein the annular main board (110; 310) is disposed on the annular base (210; 410), two branches (120; 320a, 320b) are disposed on the respective wing structures (220a, 220b; 420a, 420b) and the other branches are disposed on the annular base (210; 410), such that the bonding portions (124; 324a, 324b) are located on the mounting portions (230; 430) correspondingly. an annular main board (110; 310); a plurality of branches (120; 320a, 320b) connected with and surrounding the annular main board (110; 310) and each of the branches (120; 320a, 320b) comprising an extension portion (122; 322a, 322b) and a bonding portion (124; 324a, 324b), wherein the extension portion (122; 322a, 322b) connects the bonding portion (124; 324a, 324b) with the annular main board (110; 310) and wherein a width of each of the bonding portions (124; 324a, 324b) is greater than a width of the corresponding extension portion (122; 322a, 322b), an electronic component (52; 54) disposed on the bonding portion (124; 324a, 324b) of each of the branches (120; 320a; 320b), wherein the electronic component (52,54) is electrically connected with connection lines on the corresponding branch (120; 320a; 320b); and at least one supporting holder (200; 400) supporting the at least one flexible printed circuit board (100; 300), respectively, the at least one supporting holder (200,400) comprising: an annular base (210; 410); two wing structures (220a, 220b; 420a, 420b) extending outward from the annular base (210; 410); and a plurality of mounting portions (230; 430) located on the annular base (210; 410) and the wing structures (220a, 220b; 420a, 420b), wherein the annular main board (110; 310) is disposed on the annular base (210; 410), two branches (120; 320a, 320b) are disposed on the respective wing structures (220a, 220b; 420a, 420b) and the other branches are disposed on the annular base (210; 410), such that the bonding portions (124; 324a, 324b) are located on the mounting portions (230; 430) correspondingly. an annular base (210; 410); two wing structures (220a, 220b; 420a, 420b) extending outward from the annular base (210; 410); and a plurality of mounting portions (230; 430) located on the annular base (210; 410) and the wing structures (220a, 220b; 420a, 420b), wherein the annular main board (110; 310) is disposed on the annular base (210; 410), two branches (120; 320a, 320b) are disposed on the respective wing structures (220a, 220b; 420a, 420b) and the other branches are disposed on the annular base (210; 410), such that the bonding portions (124; 324a, 324b) are located on the mounting portions (230; 430) correspondingly.