YAG laser field lens flat field focusing lens Ftheta focusing lens
Flat field focusing lens, also known as YAG laser field lens, F-theta focusing lens, laser scanning lens, or focusing field lens, is a set of lens optical components, usually consisting of three focusing mirrors and one protective mirror. The protective mirror is coated with anti reflective film on both sides to ensure a transmittance greater than 99%. The main function is to form a uniform focal point on the entire marking plane, which is one of the core accessories of the laser marking machine. Generally speaking, in fiber laser marking machines, off-axis deflection occurs when the laser beam passes through the focusing lens system. Compared to the ideal plane, the marked surface may exhibit abnormal images or distortions. Field mirrors can be divided into f-theta lenses and telecentric lenses. Due to the high cost and expense of telecentric lenses, F-theta lenses are mainly used in industrial laser marking machines. The position of the focal length depends only on the focal length and deflection angle, simplifying the calculation method for focal length positioning.
The technical parameters of the field lens include scanning range, operating wavelength, entrance pupil, and focal spot diameter.
Working wavelength:
The selection is mainly based on the wavelength of the laser, and the coating of the field lens is determined according to the wavelength of the laser. If the wavelength of the field mirror is not consistent with the working wavelength of the laser, the field mirror will be burned out by the laser.
Entrance pupil:
If a single mirror is used and placed at the position of the entrance pupil, the diameter of the entrance pupil is equal to the diameter of the maximum available beam.
Scanning range:
The larger the scanning range of the field lens, the larger the focal point, and the greater the distortion. In order to increase the scanning range, the focal length and working distance of the reflector should also be increased. The longer the working distance, the greater the loss of laser energy. The diameter of the focused spot is proportional to the focal length As the scanning range increases, the diameter of the focused spot increases, the spot becomes less concentrated, and the accelerated laser power density decreases (the power density is inversely proportional to the secondary power of the spot diameter), which is not conducive to processing. Therefore, suitable field mirrors should be selected according to different processing areas, or multiple field mirrors with different scanning ranges should be used as backup.
Focusing spot diameter:
For the scanning system with incident laser beam diameter D, beam quality factor Q, and field lens focal length F, the focused spot diameter d=13.5QF/D (Mm). By using a beam expander, a smaller focused spot can be obtained.
Flat field focusing lenses are designed to achieve optimal performance in laser scanning or engraving systems. Field mirrors are highly suitable for applications such as carving and marking systems, image transfer, and material processing. For many applications in laser scanning and engraving systems, planar focusing lenses can achieve optimal results. F-theta field mirrors are mainly used in laser marking machines, laser measuring instruments, and scientific testing.
The technical parameters of the field lens include scanning range, operating wavelength, entrance pupil, and focal spot diameter.
Working wavelength:
The selection is mainly based on the wavelength of the laser, and the coating of the field lens is determined according to the wavelength of the laser. If the wavelength of the field mirror is not consistent with the working wavelength of the laser, the field mirror will be burned out by the laser.
Entrance pupil:
If a single mirror is used and placed at the position of the entrance pupil, the diameter of the entrance pupil is equal to the diameter of the maximum available beam.
Scanning range:
The larger the scanning range of the field lens, the larger the focal point, and the greater the distortion. In order to increase the scanning range, the focal length and working distance of the reflector should also be increased. The longer the working distance, the greater the loss of laser energy. The diameter of the focused spot is proportional to the focal length As the scanning range increases, the diameter of the focused spot increases, the spot becomes less concentrated, and the accelerated laser power density decreases (the power density is inversely proportional to the secondary power of the spot diameter), which is not conducive to processing. Therefore, suitable field mirrors should be selected according to different processing areas, or multiple field mirrors with different scanning ranges should be used as backup.
Focusing spot diameter:
For the scanning system with incident laser beam diameter D, beam quality factor Q, and field lens focal length F, the focused spot diameter d=13.5QF/D (Mm). By using a beam expander, a smaller focused spot can be obtained.
Flat field focusing lenses are designed to achieve optimal performance in laser scanning or engraving systems. Field mirrors are highly suitable for applications such as carving and marking systems, image transfer, and material processing. For many applications in laser scanning and engraving systems, planar focusing lenses can achieve optimal results. F-theta field mirrors are mainly used in laser marking machines, laser measuring instruments, and scientific testing.