An inclination sensor is provided having a level that has a liquid and a gas bubble under a covering glass in a housing. The invention has a base structure with a kingpin-receiving plate attached with respect to the top of the base structure and pivotable with respect thereto about a substantially horizontal cross-axis. The manufacture cost of the aluminum extrusion heat sink structure is lower, and the heat dissipation effect is better, so as to solve the technology problem that the volume of a traditional aluminum extrusion heat sink structure is larger caused the cost of the aluminum extrusion heat sink structure and the corresponding backlight module is higher.