Abstract: An impeller includes a hub and a plurality of blades. The blades are arranged around the hub, and each blade includes a leading edge, a blade tip, a root portion, a trailing edge, a windward side and a leeward side. The windward side including a first turning point and a second turning point, a first vertical height difference is formed from the blade tip to the first turning point, and a second vertical height difference is formed from the first turning point to the second turning point, and the first vertical height difference is greater than the second vertical height difference. The impeller apparently reduces the noise.

Abstract: A fan includes a frame, an impeller, a driving assembly and a circuit board. The frame includes an inlet, an outlet, a first accommodation space, a base and a second accommodation space, wherein the inlet and the outlet are disposed at opposite sides of the frame, and the first accommodation space is separated from the second accommodation space. The impeller is disposed in the first accommodation space and on the base. The driving assembly is disposed between the base and the impeller. The circuit board is disposed in the second accommodation space. The base includes plural first through holes, and the impeller includes plural second through holes. During the fan is operating, a first airflow is formed to flow from the inlet to the outlet, and a second airflow is formed to flow through the driving assembly via the plural first through holes and the plural second through holes.

Abstract: A diagonal fan is disclosed and includes a frame and an impeller. The frame includes an inlet, an outlet, an accommodation space and a guiding wall. The inlet and the outlet are communicated through the accommodation space. The guiding wall is extended along an axial direction to the accommodation space. The impeller is accommodated within the accommodation space and includes a conical section shell. When the impeller is rotated, an airflow flowing is generated. The outer diameter of the hub of the impeller is expended gradually in a direction from the inlet toward the outlet, so that the flowing direction of the airflow is expended gradually around the peripheral of the impeller. A gap having a spacing distance is substantially maintained to form a backflow channel. A backflow is transported through an intake section, a horizontal section and an exhaust section of the backflow channel, and converged with the airflow.

Abstract: An impeller includes a hub and a plurality of blades. The blades are arranged around the hub, and each blade includes a leading edge, a blade tip, a root portion, a trailing edge, a windward side and a leeward side. The windward side including a first turning point and a second turning point, a first vertical height difference is formed from the blade tip to the first turning point, and a second vertical height difference is formed from the first turning point to the second turning point, and the first vertical height difference is greater than the second vertical height difference. The impeller apparently reduces the noise.

Abstract: A fan frame is provided and includes a body and a first cover plate. The body includes a main surface and a first side which is substantially perpendicular to the main surface. A first channel and a second channel, which are adjacent to each other, are formed in the body, and a first space is formed among the main surface, the first side, a sidewall of the first channel, and a sidewall of the second channel. The cover plate is disposed on the body, and covers the first space, wherein a first hole is formed in the first cover plate, and the first space communicates with the external environment via the first hole.

Abstract: A fan frame is provided and includes a body and a first cover plate. The body includes a main surface and a first side which is substantially perpendicular to the main surface. A first channel and a second channel, which are adjacent to each other, are formed in the body, and a first space is formed among the main surface, the first side, a sidewall of the first channel, and a sidewall of the second channel. The cover plate is disposed on the body, and covers the first space, wherein a first hole is formed in the first cover plate, and the first space communicates with the external environment via the first hole.