Disclosed is a lightguide assembly comprising a main body (10)； a lightguide (30) with at least a portion thereof incorporated in a side wall of the main body (10)； and a light coupling seat (20) attached to an end of the lightguide (30). The lightguide (30) may be disposed within a lightguide groove (11) in a side wall of the main body (10). The coupling seat end of the lightguide (30) comprises a first portion (31) at an end portion, a narrowing section (32) connected to the first portion (31) and a second portion (33) connected to the narrowing section (32), wherein the long axis of the cross section of the lightguide (30) reduces from a first portion (31) side of the narrowing section (32) to a second portion (33) side of the narrowing section (32).
