Looking at Digital Light Processing machines, these types of 3D printing technology are almost the same as SLA. The key difference is that DLP uses a digital light projector to flash a single image of each layer all at once (or multiple flashes for larger parts).
Because the projector is a digital screen, the image of each layer is composed of square pixels, resulting in a layer formed from small rectangular blocks called voxels.
DLP can achieve faster print times compared to SLA. That’s because an entire layer is exposed all at once, rather than tracing the cross-sectional area with the point of a laser.
Light is projected onto the resin using light-emitting diode (LED) screens or a UV light source (lamp) that is directed to the build surface by a Digital Micromirror Device (DMD).
A DMD is an array of micro-mirrors that control where light is projected and generate the light-pattern on the build surface.