10.6um F-theta Lens

10.6um F-theta Lens

F-theta lenses are used in laser scanners (laser markers) and the laser wavelengths may be 355/266/532/1064nm, 10.6um and other wavelengths. We can provide full range of f-theta lenses.

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.

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

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.

1.Single-element Scan Lenses (F-theta Lenses)

1) STSL Series F-theta Lenses

STSL scanner lenses specially designed and optimized for use in CO2 laser 2-axis galvo-scanner systems with full beam diameters of up to 15.0mm. Mirror sets appropriate for use with beam diameters up to 15mm require an increase in mirror separation in comparison with smaller mirrors. These changed optical conditions are catered for by the STSL series. These single-element lenses are designed to represent the best achievable compromise for on-axis and off-axis aberrations, field flatness and F-theta characteristics, obtainable using single-element spherical-surface designs of (standard) 48mm diameter. The lens materials is ZnSe.

Part no. Focal length (mm) Scan field (mm) Back focal length (mm) Flange focal length (mm) Average spot diameter (mm)
STSL-10.6-50-75 75.2 50 x 50 74.2 78.4 171
STSL-10.6-60-90 90.1 60 x 60 90.0 94.8 174
STSL-10.6-70-101 101.3 70 x 70 101.4 106.1 181
STSL-10.6-105-149 149.1 105 x 105 150.6 155.6 219
STSL-10.6-120-175 175.0 120 x 120 177.4 178.4 243
STSL-10.6-125-179 179.2 125 x 125 181.9 187.3 247
STSL-10.6-140-201 200.6 140 x 140 203.5 208.8 269
STSL-10.6-155-226 225.5 155 x 155 228.0 232.8 296
STSL-10.6-175-249 249.4 175 x 175 253.3 258.5 320
STSL-10.6-210-298 298.0 210 x 210 302.6 307.7 373
STSL-10.6-250-363 362.6 250 x 250 368.2 373.2 445
STSL-10.6-280-394 394.4 280 x 280 401.4 406.7 481
STSL-10.6-300-433 432.7 300 x 300 441.0 446.2 525
STSL-10.6-340-482 481.8 340 x 340 490.2 495.3 581
STSL-10.6-370-529 528.8 370 x 370 538.5 543.5 634
STSL-10.6-415-592 591.7 415 x 415 586.5 589.9 717
STSL-10.6-500-717 716.5 500 x 500 730.0 734.7 850
STSL-10.6-550-782 781.6 550 x 550 797.7 802.2 925
STSL-10.6-600-848 848.4 600 x 600 859.6 863.7 1000
STSL-10.6-680-978 977.6 680 x 680 993.7 997.9 1150
STSL-10.6-840-1183 1183 840 x 840 1205 1208 1390
STSL-10.6-850-1201 1201 850 x 850 1216 1220 1410
STSL-10.6-920-1285 1285 920 x 920 1317 1321 1520
STSL-10.6-1000-1409 1409 1000 x 1000 1421 1425 1650
STSL-10.6-1120-1577 1577 1120 x 1120 1593 1596 1840
STSL-10.6-1256-1746 1746 1256 x 1256 1783 1787 2040
STSL-10.6-1500-2122 2122 1500 x 1500 2173 2177 2420
  • The lenses are meniscus form; one concave and one convex surface. The concave always faces the incident beam.
  • The mirror locations are the same for every STSL lens, so any lens can replace any other in the cell and be correctly positioned. The field sizes given, assume an optical field angle of +/-20deg.
  • Focused spot diameters assume a 15mm diameter full beam (approximately 12mm 1/e2) and TEM00 mode (M2 = 1). The ‘average’ is the mean of 25 field positions in a quadrant.
  • For all STSL lenses, the diameter is 48.0 +0/-0.1 mm, and the edge thickness is 3.0 +/-0.1 mm.

For the above lenses, we can provide a mount as option as follows:

2) STXH Series Mounted F-theta Lenses

Part No. SAR(mm) FSD(mm) FL(mm) WD(mm) L1(mm) Telecentricity(o)
STXH-10.6-50-75 50×50 0.12 75 57.5 15.5 16.1
STXH-10.6-70-100 70×70 0.18 101.3 85.7 14.4 19
STXH-10.6-90-125 90x90 0.22 128.3 111.9 13.3 21.8
STXH-10.6-110-150 110×110 0.29 150.2 135.9 13.3 23.5
STXH-10.6-140-230 140×140 0.50 238.1 227 12.8 23.6
STXH-10.6-175-250 175×175 0.54 250 238 14.0 23.9
STXH-10.6-210-300 210×210 0.61 300 288 13.8 24.5
STXH-10.6-250-360 250×250 0.80 360 352.8 12.4 26.7
STXH-10.6-300-430 300×300 1.00 430 356.5 13.8 27.8

Remark: For all STXH lenses, the lens diameter is 48.0 +0/-0.1 mm, allowed maximum input beam diameter is 14mm (20mm is available upon request), scan mirror spacing L2 is 16.5mm, outside diameter is 91mm, total length is 24mm, mount thread is M85x1mm and the lens materials is ZnSe. For the lens diameters, 38mm and 65mm are available upon request.

3) STY Series 10.6um Mounted F-theta Lenses

New Model Old Model FL
mm
WD
mm
EP
mm
SA
max
SAR, mm (round/square) FSD
µm
ODxL
mm
MT
STY-F-100-10.6 STY-10.6-70-100 100 85.5 10 ±25º Φ100/70x70 193.98 90x26.5 M85x1
STY-F-150-10.6 STY-10.6-110-150 150 131.5 12 ±25º Φ155/110x110 242.47 90.2x26.5 M85x1
STY-F-200-10.6 STY-10.6-140-200 200 185.7 15 ±25º Φ198/140x140 258.64 90.2x26.5 M85x1
STY-F-250-10.6 STY-10.6-175-250 250 244.8 15 ±25º Φ248/175x175 323.3 90x26 M85x1
STY-F-300-10.6 STY-10.6-210-300 300 298.8 12 ±25º Φ297/210x210 484.95 90x26 M85x1
STY-F-360-10.6 STY-10.6-250-360 360 350 12 ±25º Φ495/250x250 581.94 90x26 M85x1
STY-F-430-10.6 STY-10.6-300-430 430 420.2 15 ±25º Φ424/300x300 558.08 90x26 M85x1
STY-F-500-20-10.6 STY-10.6-350-500 500 552.52 20 ±28.4’’ Φ494/350x350 48.67 120x32.5 M85x1
STY-F-580-20-10.6 STY-10.6-400-580 580 663.8 20 ±25º Φ580/400x400 562.54 120x47 M85x1

4) STH Series 10.6um Mounted F-theta Lenses

Model FL, mm SAR, mm FSD, mm MT
STH-10.6-50-63 63 50x50 0.2 M85x1
STH-10.6-70-100 100 70x70 0.2 M85x1
STH-10.6-110-160 160 110x110 0.2 M85x1
STH-10.6-140-230 230 140x140 0.2 M85x1
STH-10.6-175-254 254 175x175 0.2 M85x1
STH-10.6-210-300 300 210x210 0.2 M85x1
STH-10.6-250-360 360 250x250 0.25 M85x1
STH-10.6-300-450 450 300x300 0.35 M85x1
STH-10.6-400-592 592 400x400 0.2 M85x1
STH-10.6-600-650 650 600x600 0.7 M85x1

2. Mounted 2-element F-theta Lenses

1) STU2 Series Mounted 2-element F-theta Lenses

These doublet (STU2) and triplet scanning (STU3) lenses are intended to work with the same configuration of scanning mirrors and beam sizes as the STSL single-element lenses, but are offered at the shorter focal lengths where better performance is possible. The doublets have focal lengths from 75 to 300mm. Above 300mm the benefits of using a doublet are not great. The triplets are offered in two focal lengths, 75 and 100mm. These give diffraction limited performance and even further improvement over the corresponding doublet.

All the lenses are made from laser grade ZnSe. Each of the lenses comes in a black anodized aluminium mount and can also be fitted with a ZnSe protection window as an option.

Specifications:

  • Material: All elements and protection window made from Laser Grade ZnSe.
  • Mount details: See Figure 10.51.
  • Beam diameter: Up to 15mm (12mm 1/e2)
  • Optical scan field: +/-20° in X and Y.
  • Focal length: Within 1%.
  • Absorption: < 0.25% per element.
  • Transmission: > 99.6% per element coated AR/AR for 10.6mm.
  • Damage threshold: CW 3000W/mm at 10.6mm.
Part no Scan field (mm sq) FL (mm) Focus size (mm) Standard deviation of spot (mm) WD with window (mm)
STU2-10.6-50-75 50 75.0 118 25 62.03
STU2-10.6-70-100 70 100.0 139 22 89.34
STU2-10.6-105-151 105 151.4 171 0 150.84
STU2-10.6-140-200 140ed 200.0 225 0 215.73
STU2-10.6-175-250 175 250.0 282 0 263.17
STU2-10.6-210-300 210 300.0 338 0 313.87

3. Mounted Triple-element F-theta Lenses

1) SL3 Series 3-element F-theta Lenses

Part No. Wavelength (um) FL(mm) WD (mm) SA SAR(mm²) EP
(mm)
a1
(mm)
L1
(mm)
Focus size (um) MT Length (mm)
SL3-9.4-50-80W 9.4 80 89.4 +/- 25۫ 50X50 14 18 18 84.5 M85X1 39.20
SL3-9.4-60-105Z 9.4 105 60.1 +/- 25۫ 60X60 14 18 21 88.5 M85X1 86
SL3-10.6-50-80W 10.6 80 89.4 +/- 25۫ 50X50 14 18 18 84.5 M85X1 39.20
SL3-10.6-60-105Z 10.6 105 60.1 +/- 25۫ 60X60 14 18 21 88.5 M85X1 86

2) STU3 Series Scan Lenses

  • focal lengths 75 and 100mm respectively
  • the 75mm focal length lens is also nearly telecentric (see below) with the focused beam less than 5° to the normal diffraction limited performance over the entire image plane
  • virtually zero F-theta error
  • can be fitted with a protective window

Custom designs:

The designs listed below are for a specific set of conditions that may not suit everyone’s requirement. If you need a lens for another set of conditions, such as, a larger beam, different field size or focal length, or a telecentric design, then please contact us.

Part No. Wavelength (um) FL (mm) SAR (mm) EP (mm) Focus size (mm)
STU3-10.6-50-75 10.6 75 50x50 15 89
STU3-10.6-70-100 10.6 100 70x70 15 113

Focused spot size comparison between STSL, STU2 and STU3

Dimension of STU2 and STU3

4. STG Series Telecentric F-theta Lenses

Part No. FL (mm) SA max (±°) SAR (mm) EP (mm) FSD (um) Length (mm) WD (mm)
STG-10.6-50-100G 100 20 50*50 25 60 93 106
STG-9.6-50-110Z 110 14.5 50*50 15 140 99 97
STG-9.6-70-140Z 140 20 70*70 15 126 142 124

Custom-design and –made available upon request.