| CPC B29C 64/135 (2017.08) [B29C 64/232 (2017.08); B29C 64/245 (2017.08); B29C 64/255 (2017.08); B29C 64/264 (2017.08); B33Y 10/00 (2014.12); B33Y 30/00 (2014.12)] | 5 Claims |

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1. A 3D printer comprising:
a resin tank accommodating a resin material;
a molding plate movable up and down in the resin tank, and supporting a printed object formed by stacking a plurality of unit forming layers in sequence;
an up-and-down movement actuator actuating at least one of the resin tank and the molding plate to move up and down;
an exposure unit emitting light toward the molding plate; and
a lens sheet comprising:
a first material layer comprising a molding surface facing the molding plate and a light receiving surface facing the exposure unit, disposed between the molding plate and the exposure unit, formed with a plurality of fine lens units for converging and diffusing the light from the exposure unit on one surface, and
a second material layer comprising a concavo-convex portion to be engaged with the fine lens unit of the first material layer,
wherein the first material layer has a higher refractive index than the second material layer,
wherein the first material layer is thicker than the second material layer, and
wherein in a state in which an external force is applied to at least of the first material layer or the second material layer, the first material layer is that is less deformable than the second material layer.
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