Heat exchanger fin, heat exchanger, indoor unit and air conditioner

A heat exchanger fin, comprising:

• a fin body, comprising an air outlet contour line arranged at one side and an air inlet contour line arranged at other side, and provided with refrigerant pipe mounting holes;
• wherein
• the fin body is curved from a center of the heat exchanger fin to two ends of the heat exchanger fin;
• a distance between the air inlet contour line and the air outlet contour line of the fin body, on a straight line of a curvature radius of the air outlet contour line of the fin body or on a straight line of a curvature radius of the air inlet contour line of the fin body, decreases from the center of the heat exchanger fin to the two ends of the heat exchanger fin;
• the fin body is concave in a direction from an air inlet side to an air outlet side of the fin body;
• a distance between adjacent refrigerant pipe mounting holes is positively correlated with a diameter of the refrigerant pipe mounting holes:
• both the distance between adjacent refrigerant pipe mounting holes and the diameter of the refrigerant pipe mounting holes decreases from the center of the heat exchanger fin to the two ends of the heat exchanger fin;
• and
• number of the refrigerant pipe mounting holes is decreased from the center to the two ends of the heat exchanger fin.