Abstract: A three-dimensional printing system includes a build device and an optical projection engine. The build device includes a curing tank, a photocurable material and a build platform, and the photocurable material and the build platform is disposed in the curing tank. The optical projection engine has a zoom lens for projecting image beams with at least a first pixel size and a second pixel size on the build platform to cure the photocurable material, and the first pixel size is different to the second pixel size.

Abstract: A three-dimensional printing system includes a build device and an optical projection engine. The build device includes a curing tank, a photocurable material and a build platform, and the photocurable material and the build platform is disposed in the curing tank. The optical projection engine has a zoom lens for projecting image beams with at least a first pixel size and a second pixel size on the build platform to cure the photocurable material, and the first pixel size is different to the second pixel size.

Abstract: A projection lens for a projection device having a light valve is provided. The light valve provides an image light beam. The projection lens includes a first lens group, a second lens group and a reflecting lens group. The second lens group is disposed between the first lens group and the reflecting lens group. The first lens group has positive refractive power. The second lens group has positive refractive power and includes a plurality of lenses and an aperture stop located between the lenses. An angle of a field of view of the second lens group is less than 100 degrees. The reflecting lens has negative reflective power and has a curved reflecting surface to reflect the image light beam passed through the second lens group.

Abstract: A projection lens for a projection device having a light valve is provided. The light valve provides an image light beam. The projection lens includes a first lens group, a second lens group and a reflecting lens group. The second lens group is disposed between the first lens group and the reflecting lens group. The first lens group has positive refractive power. The second lens group has positive refractive power and includes a plurality of lenses and an aperture stop located between the lenses. An angle of a field of view of the second lens group is less than 100 degrees. The reflecting lens has negative reflective power and has a curved reflecting surface to reflect the image light beam passed through the second lens group.