- High light transmittance, high output laser energy
- Marking area is optional from 100mm to 300mm
- High-quality coating, good protection, uniform laser light
- Suitable for a variety of fiber laser marking machines with a laser wavelength of 1064nm
- High quality, not easy to damage
What can F theta lens do for you?
In recent years, laser marking technology has become one of the largest application areas of laser processing, and its features such as fast marking speed, clear writing, strong anti-counterfeiting function, and low pollution have attracted wide attention from the industry. Working near the focal plane of the objective lens. The lens is called an F-theta lens.
In the marking system, the laser beam passes through the F theta lens system and will produce off-axis deflection. Relative to an ideal plane, abnormal images or distortion will appear on the marking surface. Simply put, the laser is scattered by the F theta lens to form a relatively fixed focal length and marking range. For example, our usual marking range for lasers is 100mm x 100mm. If you want to mark a larger range of content, you need to replace the F-theta lens with a large marking range.
What are the different effects of using different f-theta lenses for the same laser machine?
Here is the video we test the lens （marking area 100mm x 100mm）and the lens （marking area 200mm x 200mm）
Because the laser output energy is constant, so when you replace a larger range lens, the output laser energy will be reduced, because the laser energy is scattered, so we usually recommend that customers choose high output power laser marking machines, such as 30W, 50W, 60W, so that it can adapt to a larger marking area F theta lens
How to Replace the F- theta Lens and What Settings to Do after Replacement?
As you can see from the above video, it is very easy to replace the field lens, but we still have a lot of work to do after replacing it, you need to adjust the focal height of the laser head and adjust the accuracy of the marking area of the laser head, then adjust the position of the red light positioning offset, etc.
What are the Details of Our F Theta Lenses?
| Type | F160-W1064 | F160-W1064 | F254-W1064 | F254-W1064 | F435-W1064 |
|---|---|---|---|---|---|
| Focal length | 162mm | 210mm | 254mm | 300mm | 435mm |
| Back focal length | 194.62mm | 256.3mm | 298.75mm | 364.64mm | 486.66mm |
| Work wavelength | 1064nm | 1064nm | 1064nm | 1064nm | 1064nm |
| Scan angle | +/-27 degree | +/-28 degree | +/-28 degree | +/-28 degree | +/-28 degree |
| Squire field size | 110mm*110mm | 150mm*150mm | 175mm*175mm | 207mm*207mm | 300mm*300mm |
| Incident beam diam.(Max.) | 12mm | 16mm | 16mm | 16mm | 18mm |
| Recommended mirror separation | 16mm | 16mm | 16mm | 16mm | 16mm |
| Y mirror distance | 16mm | 18mm | 18mm | 18mm | 18mm |
| X mirror distance | 32mm | 34mm | 34mm | 34mm | 34mm |
| Encircled Energy(80% energy) | 12.5um | 18um | 20um | 21um | 22um |
| Max Diameter of lenses | 76mm | 91mm | 91mm | 96mm | 115mm |
| Mounting thread | M85*1 | M85*1 | M85*1 | M85*1 | M85*1 |
How to Choose the Right F- theta Lens for Your Needs?
To select an F theta lens, the main technical parameters to consider are the laser working wavelength, incident pupil, scanning range, and focused spot diameter.
Working wavelength: mainly depends on the wavelength of the laser, the lens is coated in the given laser wavelength. If the lens is not used in the given wavelength range, then it will be burned by the laser. Normally Fiber laser working wavelength is 1064nm.
Incident light pupil: If a single lens is used, the reflector is placed at the entrance pupil, and the diameter of the maximum usable beam is equal to the diameter of the entrance pupil.
Scanning range (marking range): The larger the range that the field lens can scan, the more popular it is by users. However, if the scanning range is increased, the focus spot becomes larger, and the distortion degree also increases. In addition, to increase the scanning range, the F theta lens focal length and working distance should also be increased. The working distance is longer, which inevitably leads to the loss of laser energy.
There is also a focus spot diameter that is proportional to the focal length, which means that increasing the scanning range, focus spot diameter followed by increasing the spot is not fine enough, the laser power density decreases very quickly, which is not conducive to processing. Therefore, it is not that the larger the marking range, the better the F theta lens, you need to choose the appropriate one according to your needs.
Focused spot diameter: For a scanning system with incident laser beam diameter D, field lens focal length F and beam quality factor Q, the focused spot diameter d = 13.5QF/D (mm). Therefore, a beam expander can be used to obtain a smaller focused spot.