Infrared LF estimated in two redshift bins with the 1/V_max method. Red and dark blue squares are obtained using and respectively (see text). Asterisks show the local reference taken from Sanders et al. (2003) and the dotted line represents the best-fit to these data points with a double power law function with fixed slopes (see text). The dashed line represents the best fit of the infrared LF assuming that the shape of the infrared LF remains the same since zs0. The dark shaded area span all the solutions obtained with the χ² minimization method and compatible, within 1σ, with our data points. In the first redshift panel, we reproduce in green, blue, yellow and red the best fit of the LF obtained at 0.4 < z < 0.7, 0.7 < z < 1.0, 1.0 < z < 1.3 (Magnelli et al. 2009), and 1.8 < z < 2.3 respectively.