System and method for computed axial lithography (CAL) for 3D additive manufacturing

A method of forming a three dimensional (3D) object, comprising:

• providing a volume of photo-curable resin contained within an optically transparent resin container, a z axis extending through the volume of photo-curable resin and an x′ axis extending normal to the z axis;
• rotating the optically transparent resin container about the z axis while directing optical projections in a fixed x′ direction from a stationary optical subsystem at the resin container in sequential fashion, along different angles θ relative to the resin volume coordinate system (x,y,z) as the resin volume rotates;
• and
• wherein a two dimensional (2D) projection function of the optical projection is controlled at each angle θ to deliver a controlled 3D exposure dose,
• while over a fixed temporal exposure period, which includes projections from multiple angles θ to produce a summed 3D exposure dose in the resin volume, the summed 3D exposure dose being sufficient to cause photocuring in desired regions and not in undesired regions;
• and
• further comprising arranging the optically transparent resin container within a secondary container, where the secondary container is filled with a fluid which has a refractive index matched to that of the resin.

A method of forming a three dimensional (3D) object, comprising:

• providing a volume of photo-curable resin contained within an, optically transparent resin container, a z axis extending through the volume of photo-curable resin and an x′ axis extending normal to the z axis;
• arranging the optically transparent resin container within a secondary container, where the secondary container is filled with a fluid which has a refractive index matched to that of the resin;
• using an optical subsystem to generate an optical two dimensional (2D) projection;
• causing at least one of the 2D projection, or the resin container and the secondary container, to rotate relative to the other to receive the optical 2D projection around a complete circumference of the volume of photo-curable resin while maintaining the optical 2D projection directed through the volume of photo-curable resin, and the fluid within the secondary container;
• and
• wherein a two dimensional (2D) projection function of the 2D projection is controlled at each angle θ to deliver a controlled 3D exposure dose over a fixed temporal exposure period, and where a plurality of 2D projections is generated from a plurality of angles θ, and where the plurality of 2D projections are summed to produce a 3D exposure dose in the resin volume which is sufficient to cause photocuring in desired regions, while being insufficient to cause photocuring in undesired regions.