ABSTRACT
F-theta scan lenses are used to scan a document for either printing or reading. A scanning device is situated an external entrance pupil; it may be a rotating polygon, rotating mirror, mirror galvanometer, piezoelectric deflector, etc. The document to be scanned is usually flat. In the case of the rotating polygon that is rotating at a high, uniform angular velocity, for the image positions to be uniformly spaced it is necessary that the image height be proportional to the scan angle (not to the tangent of the angle as in a photographic lens). This linear requirement is generally true for the other scanning devices. I m a g e h e i g h t = K F θ , https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315222295/bd2ad0d9-a48e-40ac-8986-c51474069cbd/content/eq108.tif"/>
