Flat field focus lens, tseem hu ua field lens (f-theta focus lens), yog lub lens kev tshaj lij. Lub hom phiaj yog los tsim ib qho kev sib koom ua ke tsom qhov chaw ntawm lub laser beam nyob rau hauv tag nrho cov ua dav hlau. Nws yog ib qho tseem ceeb heev rau laser tu tshuab.
