NOVELTY - The method comprises providing a substrate provided with a layer of a liquid medium comprising solute or dispersed particles, modulating a surface temperature of the layer according to a heat pattern to induce movement of the solute or the dispersed particles, and partially evaporating the liquid medium to deposit part of the solute or the dispersed particles during and/or after the modulation step. The modulation step comprises irradiating the layer with an electromagnetic radiation according to an irradiation pattern.    USE - The method is useful for controlling the deposition of a solute from a solution or dispersed particles in a liquid medium e.g. organic solvent, where: the deposited solute or particle is useful to form a patterned device using an apparatus by roll-to-roll processing (all claimed); and the patterned device is an organic light emitting diode or an organic photovoltaic device.    ADVANTAGE - The method provides a high degree of flexible and noninvasive control over the evaporation of the liquid medium.    DETAILED DESCRIPTION - The method comprises providing a substrate provided with a layer of a liquid medium comprising solute or dispersed particles, modulating a surface temperature of the layer according to a heat pattern to induce movement of the solute or the dispersed particles, and partially evaporating the liquid medium to deposit part of the solute or the dispersed particles during and/or after the modulation step. The modulation step comprises: irradiating the layer with an electromagnetic radiation according to an irradiation pattern; measuring a local thickness and/or a concentration of the solute or the dispersed particles; and adjusting the heat pattern according to the measured local thickness and/or the concentration of the solute or the dispersed particles. The electromagnetic radiation is an infrared laser light having a wavelength of 2.5-11 mu m. The irradiation pattern is controlled by a digital multi-mirror device (DMD). The substrate, the liquid medium and/or the solute or the dispersed particle has an absorption peak coinciding with the wavelength of the electromagnetic radiation. The adjusting step comprises: determining the uniformity of the thickness of the layer and/or the concentration of the solute or the dispersed particles; and changing the heating pattern so as to increase the uniformity of the thickness of the layer and/or the concentration of the solute or the dispersed particles. The substrate is contacted with a material having the absorption peak. INDEPENDENT CLAIMS are included for:    (1) a patterned device; and    (2) an apparatus for irradiating selected areas in a layer of a liquid medium and for the manufacture of the patterned device by roll-to-roll processing.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic view of a system for performing a method of controlling the deposition of a solute from a solution or dispersed particles in a liquid medium.    Infrared laser source (10)    Optical fiber (20)    Beam conditioning and homogenization optics (30)    Beam dump (50)    Projection optics. (60)