The optical system of traditional exposure machine is mainly composed of light source (high pressure spherical mercury lamp), ellipsoid reflector cup, cold light mirror, transmission compound eye lens array, dichroic mirror and spherical parallel mirror.
The light emitted by the light source is focused by an ellipsoidal reflector cup, then reflected by a cold mirror to a compound-eye lens array field mirror. The light emitted from the projection lens reaches a dichroic mirror. The ultraviolet part of the spectrum is transmitted by 50%. After 50% reflection, it reaches two symmetrically distributed large spherical parallel mirrors, which are collimated and reflected to the sun plate and into the PCB plate. Line exposure.
