Fan blade and air supply device

An air supply device, comprising:

• a fan blade, comprising:
• a hub;
• a blade connected to a circumferential side face of the hub, wherein the blade presents a circular shape, an inner annular surface of the blade encloses a hollow area, or the inner annular surface of the blade and the circumferential side face of the hub enclose a hollow area;
• wherein, in a radial direction of the hub, an end of the blade connected to the hub is a root part of the blade, and an end thereof away from the hub is an end part of the blade;
• in a direction from the end part to the root part, at least a portion of an area of the blade is a first segment part, and the first segment part comprises a first inner annular surface and a first outer annular surface;
• in an axial direction of the hub, the first inner annular surface and the first outer annular surface turn direction at the end part, through torsion so that the first inner annular surface is connected to the first outer annular surface, and the first inner annular surface and the first outer annular surface on both sides of the end part do not overlap, an outer contour of a cross-section of the blade comprises a first smooth convex curve and a second smooth concave curve, and the first smooth convex curve and the second smooth concave curve are snapped to form the outer contour of the cross-section of the blade;
• and
• a driving part connected to the hub, wherein the driving part is used for driving the fan blade to rotate.