The conductive plate 72 defines a plurality of retaining holes 720 therein along a middle line thereof. A plurality of screws 710 extend through the LLS 40 to threadedly engage into the retaining holes 720, thereby fixing the LLS 40 onto a bottom surface of the conductive plate 72. The conductive plate 72 defines a plurality of heat-dissipating strips 722 on a top surface thereof to enlarge a heat dissipation area thereof.
The connecting member 70 comprises also two T-shaped latching slots 74 and another two U-shaped latching slots 75
The LLS 40 comprises an elongated printed circuit board 42 and a plurality of LEDs 44 mounted on the printed circuit board 42. The LEDs 44 are arranged in three rows along a length direction of the printed circuit board 42. In each row, the LEDs 44 are arranged at equal intervals. A plurality of fixing holes 420 are defined therein along the length direction of the printed circuit board 42 and located between the three rows of LEDs 44. The screws 710 extend through the fixing holes 420 to threadedly engage into the retaining holes 720 of the connecting member 70, thereby fixing the LLS 40 onto a central portion of the bottom surface of the conductive plate 72 of the connecting member 70, e.g., shown in