1064nm F-Theta Lens

Lenses used in combination with XY galvanometer scanner are called ƒ-theta lenses, plane field objectives or simple scan lenses. ƒ-theta lenses are used in various applications from industrial material processing, drilling, welding of synthetic material and cutting in addition to medical and biotechnology (confocal microscopy, ophthalmology) to science and research. The design and the quality of the optical components are playing a decisive role.

A standard lens focuses the laser beam on a spherical plain in contrast to an ideal flat or plane field. The use of ƒ-theta lenses provides a plane focusing surface and almost constant spot size over the entire XY image plane or scan field. The position of the spot on the image plane is directly proportional to the scan angle. Telecentric ƒ-theta lenses focus the laser beam so it is almost perpendicular (within 1 degree) to the work surface over the entire scan field. This ensures the spot is round even in the corners of the scan field and if holes or channels are machined, they are perpendicular to the work surface.

Color corrected ƒ-theta lenses are designed to accommodate multiple wavelengths. Normally each wavelength would focus to a different point on the work surface. In a color corrected lens the focal point for each wavelength coincide. This is achieved by scheduling an ideal combination of different glass types for the various lens elements in the lens. Color corrected ƒ-theta lens are primarily used for simultaneously viewing the work surface through the scan lens with a camera while laser processing. Another common application for color corrected scan lenses are for use in confocal scan microscopes which require a broad range of visible wavelengths.

Telecentric ƒ-theta lenses provide a beam with perpendicular incidence onto the image surface. This is necessary for drilling holes and structuring surfaces in the third dimension (depth). The downside is generally a smaller focal plane compared to a non-telecentric lens, because the size of the frontal lens elements has to be larger than the scan area. Sill offers for both kinds of ƒ-theta lenses a large variety of options and focal distances.

The telecentricity error specifies the deviation of the laser beam from perpendicular. Usually it is maximum in the corner of the XY scan field. Note, that the telecentricity error is always zero on the optical axis. The telecentricity error or maximum incidence angle is a sign of quality for telecentric or entocentric lenses. Perfect telecentricity is only possible if all light comes from the object sided focus. In principle you can say: the larger the space between the mirrors, the larger the distance from one mirror to the object sided focus the larger the telecentricity error.

We mainly provide 3 series of f-theta lenses, STY, STS and STJ.

Description of STY series f-theta Lenses: STY-xxxx-yyy-zzz-dd-A
STY--- STY series laser f-theta lenses
xxxx-- laser wavelength, 1064 means 1064nm, 10.6 means 10.6um.
yyy---- mark field (scan field), yyy x yyy mm
zzz---- effective focal length in mm
dd------  entrance pupil (allowed maximum input laser beam diameter) in mm (option)
A------ others

Remark: (1) The f-theta lens consists of 3 lenses and one protective window/glass. The coating is a di-electric layer. The transmission is >99% at 1064nm. Two sides of the protective glass are AR-coated at 1064nm.

(2) In the following tables, the abbreviations are as follows: FL means effective focal length; EP means max. input beam diameter; SAR means scan area, AS means aperture stop; WD means working distance; OD means max. outside diameter; MT means mount thread, fs means fused silica, SA means max. full diagonal scan angle; L2 (a1) means recommended mirror separation; a2 means 2nd mirror to flange, L1 means the distance 2nd mirror and scan lens, SL means scan length, Length means the total length of the scan lens, FSD means focused spot diameter, WC means water cooled, Max. IA means telecentriccity angle.

(1) STY Series 1064nm Scan Lenses (F-tehta Lenses)

STY Series F-theta Lens (Fused Silica)

STY Series 1064nm F-theta Lens (Optical Glass)

STH Series 1064nm F-theta Lens

STW Series 1064nm F-theta Lenses

STC Series 1064nm F-theta Lenses

STY Series 1064nm Telecentric F-theta Lens (Fused Silica)

STY Series 1064nm Telecentric F-theta Lens (Optical Glass)

Protection windows used in f-theta lens: we have the protection windows in the dimensions 75x1.7mm, 80x1.7mm and 113.5x2mm, which are coated on both sides at 532 - 1064nm.

If you can not find a suitable f-theta lens, please download the form here and email us your filled form. We can custom-desing and make the lenses according to your specific requirements.