Abstract: A device, a computer program, a computer readable medium and a method for controlling focus of a laser beam during a micro sweep are disclosed. The laser beam is received to an acousto-optic deflector, and acoustic waves are provided to the acousto-optic deflector. The acoustic waves are varied in frequency over time to vary a deflection angle of the laser beam over time thereby achieving the micro sweep of the laser beam. Furthermore, a rate of variation in frequency of the acoustic waves is adapted over a time of the micro sweep in such a way that differences in frequencies over the time of the micro sweep of the acoustic waves are caused in the acousto-optic deflector over a width of the laser beam in a direction parallel to the micro sweep when passing through the acousto-optic deflector, where the differences in frequencies over the time of the micro sweep are such that they cause a desired focus of the laser beam in a direction parallel with the micro sweep over the micro sweep.

Abstract: A method for preparing pixel data for writing with SLM comprises obtaining (S10) of data representing a pattern. The data is rasterized (S20) to a grid of pixels. The rasterizing comprises assigning (S22) of an edge adjustment value to pixels covering an edge of the pattern. The rasterized pattern is divided (S30) into a number of rasterized pattern planes associated with a respective radiant exposure. The sum of radiant exposures for a completely covered pixel exceeds (S32) a threshold for activating a radiation sensitive layer on a substrate, onto which the pattern is to be printed. The sum of radiant exposures for a pattern edge pixel corresponds (S34) to a quantity sufficient to move a position of where the sum of radiant exposures reaches the activation threshold a distance that corresponds to the edge adjustment value. Data representing the rasterized pattern planes are outputted (S40).

Abstract: A rasterization method of patterns with periodic components for SLMs is presented, comprising obtaining (S10) of an original pattern, having a periodicity. A first pattern main period is determined (S21). Image area and a first pitch of imaged elements are obtained (S31). The original pattern is scaled (S41) by a first raster scaling factor. The scaled pattern is cropped (S51) to comprise a first integer number of repetitions of the pattern items presenting a periodicity in the first direction that is covered by the image area, giving a rasterized pattern adapted to the intended pattern generator. The rasterized pattern is associated with data representing the first scaling factor. A writing method comprises obtaining of the rasterized pattern. Elements of the SLM in the pattern generator falling outside the rasterized pattern are set to be disabled. The rasterized pattern is written with an optical scaling to a target surface.

Abstract: A device, a computer program, a computer readable medium and a method for controlling focus of a laser beam during a micro sweep are disclosed. The laser beam is received to an acousto-optic deflector, and acoustic waves are provided to the acousto-optic deflector. The acoustic waves are varied in frequency over time to vary a deflection angle of the laser beam over time thereby achieving the micro sweep of the laser beam. Furthermore, a rate of variation in frequency of the acoustic waves is adapted over a time of the micro sweep in such a way that differences in frequencies over the time of the micro sweep of the acoustic waves are caused in the acousto-optic deflector over a width of the laser beam in a direction parallel to the micro sweep when passing through the acousto-optic deflector, where the differences in frequencies over the time of the micro sweep are such that they cause a desired focus of the laser beam in a direction parallel with the micro sweep over the micro sweep.

Abstract: A rasterization method of patterns with periodic components for SLMs is presented, comprising obtaining (S10) of an original pattern, having a periodicity. A first pattern main period is determined (S21). Image area and a first pitch of imaged elements are obtained (S31). The original pattern is scaled (S41) by a first raster scaling factor. The scaled pattern is cropped (S51) to comprise a first integer number of repetitions of the pattern items presenting a periodicity in the first direction that is covered by the image area, giving a rasterized pattern adapted to the intended pattern generator. The rasterized pattern is associated with data representing the first scaling factor. A writing method comprises obtaining of the rasterized pattern. Elements of the SLM in the pattern generator falling outside the rasterized pattern are set to be disabled. The rasterized pattern is written with an optical scaling to a target surface.

Abstract: The present invention relates to a method to reduce the effect of jitter in a pulsed laser system, the method comprising the actions of sending a trigger signal to a power system for producing laser pulses, delaying said trigger signal a first period of time, detecting a period of time between said sending of said triger signal and a corresponding laser pulse, calculating a difference between said detected period of time and a requested period of time, correcting said first period of time in a following laser pulse by said calculated difference. The invention also relates to a pulsed laser system and a laser pattern generator.