Abstract: A light device includes a light transmission tube, a heat sink, a light bar, and two end caps. The light transmission tube has two securing parts. Each of the securing parts includes a first rib and a second rib, and a guide-track groove is formed between the first and second ribs. The heat sink includes a first plate body and a second plate body. The first plate body is curved and abutted on an inner wall of the light transmission tube, and the second plate body is curved toward the first plate body. Two terminals of the first plate body are connected to two terminals of the second plate body to form two connecting parts for coupling with the guide-track grooves. The light bar is disposed on the second plate body. The end caps are respectively connected to two terminals of the light transmission tube.

Abstract: A lamp tube includes a light transmission tube, a heat dissipation structure, a die bonding substrate and at least one light source. The light transmission tube includes first guiding rails disposed on opposite positions of the inner wall thereof. The first guising rails and the inner wall of the light transmission tube form first grooves. The heat dissipation structure inserts into the light transmission tube, and includes a die bonding area, extending arms downwardly extended from opposite sides of the heat dissipation structure, and connecting arms connected to the extending arms. Each of the extending arms includes second guiding rails and second grooves. The second guiding rail is engaged with the first groove, and the first guiding rail is engaged with the second groove. The die bonding substrate is placed on the die bonding area. The light source is placed on the die bonding substrate.