Abberation-Corrected Focusing Lenses (1.5″)
The justification for use of aberration-corrected lenses is given in Technical Data Section 20.0,
where 1.1″ size components are dealt with. Some CO2 laser beams are larger in diameter than
suitable for the 25mm clear aperture of the optics detailed in Section 20.0. Here we present two larger
sizes of aberration-corrected focusing lenses with 34mm and 38mm clear apertures. At these
increased apertures, longer focal lengths may sensibly be offered, since the relative performance
compared with meniscus lenses depends upon F-number (Section 20.0).
The 14TF series have 34mm clear aperture and standard models include 38mm, 50mm, 63.5mm,
95.3mm and 127mm focal lengths. The 15TF series have 38mm clear aperture, and standard models
include 38mm, 50mm, 63.5mm, 95.3mm and 127mm focal lengths. For more details see Technical
Data Sections 21.1 and 21.2 respectively.
Water cooling mounts
Water cooling mounts, accepting the two series of lenses and providing indirect water cooling, are
detailed in Technical Data Section 21.3. Model ‘WMB’ mount is designed to accept the M15 size
lens cell in which 14TF lenses are housed. The mounting thread for model WMB is male, 44.0
diameter x 1.0 pitch x 6mm long. Model ‘WMC’ mount is designed to accept the special cell in which
15TF lenses are housed. The mounting thread for the model WMC is male, 44.0 diameter x 1.0 pitch
x 6mm long.
The CFF38 focusing head has a 38mm clear aperture and is ideal for use with both 14TF and 15TF
series lenses (Section 63.3). The BE25 series of beamexpanders has an output aperture compatible
with the 14TF and 15TF series of lenses (Section 67.0).
Typical applications for aberration-corrected focusing lenses include ceramics scribing and profiling;
anilox processes; perforation of cigarette filter tips and any other process where high energy
density and small spot size is critical. Where aberration-corrected lenses are substituted for existing
single element lenses of inferior performance, the user may find that modifications to his nozzle/
assist gas/gas pressure are needed to obtain the maximum benefit from the improved optics. This
is due to the smaller kerf-width that will occur from achieving a reduced focused spot size.
The following Data Sections 21.1 and 21.2 describe two element corrected lenses with clear
apertures of 34.0 and 38.0mm respectively. These lenses are designed for moderate assist gas
pressures as follows:
14TF series – up to 6 bar (90 psi)
15TF series – up to 4 bar (60 psi)
For very high gas pressures ULO Optics can offer non-standard designs of aberration-corrected
lenses and appropriate high gas pressure nozzles. (These can be supplied to special order and are not held