Patent ID: 11919228
Assignee: FORMLABS, INC.
Field: Other special machines (Mechanical engineering)
Classification: CPC B | IPC B

Claim 7:
8. An additive fabrication device, comprising:
a build platform;
a light processing unit configured to move in a first direction with respect to the additive fabrication device, the light processing unit including:
an optical scanning device,
a light source, and
a light sensor;

a container including a lower film, an upper film spaced apart from the lower film, and a skirt attached to the upper film that hangs down to provide a contained space between the upper film and lower film and to prevent contamination from entering the contained space; and
one or more processors configured to:
operate the light source to emit light;
operate the optical scanning device to direct the emitted light to a plurality of locations on the film;
operate the light sensor to detect different intensities of light reflected from the film for each of the plurality of locations on the film;
detect one or more contaminants on the film by comparing the different intensities of the reflected light from the film; and
in response to detecting the one or more contaminants on the film, calculate respective locations of the one or more contaminants on the film.