Disclosed is a lightguide assembly, comprising a main body； a lightguide with at least a portion thereof incorporated in a side wall of the main body； and a light coupling seat attached to an end of the lightguide. The coupling seat end of the lightguide comprises a first portion at an end portion, a narrowing section connected to the first portion and a second portion connected to the narrowing section, wherein the long axis of the cross section of the lightguide reduces from a first portion side of the narrowing section to a second portion side of the narrowing section.
