US Patent 10036199 Window blind

A window blind includes a headrail, a bottom rail, and a plurality of slats. The slats are horizontally suspended between the headrail and the bottom rail through ladder tapes. Each ladder tape has two warps, wherein an end of the warps is connected to a ladder drum, and another end thereof passes through the bottom rail to be connected thereto. When the ladder drum is rotated, the ladder tapes could be pulled smoothly, and the slats supported by the ladder tapes could be tightly closed. Whereby, the window blind could provide a good shielding effect.