F-theta Lens For Laser Marking Scanner

Product Description

F-theta objective is normally used together with a galvo-based laser scanner. It has 2 main functions: focus the laser spot and flatten the image field, as shown in the image below. The output beam displacement is equal to f*θ, thus was given the name of f-theta objective.By introducing a specified amount of barrel distortion in a scanning lens, the F-Theta scanning lens becomes an ideal choice for applications that require a flat field on the image plane such as laser scanning, marking, engraving and cutting systems. Depending on the requirements of the application, these diffraction limited lens systems can be optimized to account for wavelength, spot size, and focal length, and distortion is held to less than 0.25% throughout the field of view of the lens.

F-theta len has several performance metrics as below:

1.Scan Field

The bigger field that the lens scans, the more popular the f-theta lens is. But too big scan field may cause many problems, such as big beam spot and deviation.

2.Focal length

Focal length (it has something to with f-theta lens working distance, but not equal to working distance).

a.Scan field is proportional to the focal length-bigger scan field will inevitably lead to longer working distance, which means more laser energy consumption.

b.The diameter of focused beam is proportional to the focal length, which means that when the scanning field increase to certain extent, the diameter is very big.The laser beam is not focused well, the laser energy density decreases badly ( the density is inversely proportional to the square of diameter) and cannot process well.

c. The longer the focal length is, the bigger the deviation is.

1064nm f-theta lens

F-theta Lenses can shoot and form the image of objects of limited distance. It provides full glass high-performance lens, and different lenses meet the functions of A3, A4, barcode scanning. It is applied to the flatbed scanner and high shot instrument equipment. The lens is close to the diffraction limit and has small distortion, which meets the requirements of use.

The principles of F-theta Lenses:

To change the directions of beams through moving the scanner. To make the movement become the one of the focus on the focal plane by focus lens’s focusing. Laser scanning can be divided into pre-objective scanning and scanning after the objective lens. Usually scanning device with the high requirement is pre—objective scanning.

The special characteristics of scanning objective:

1. Scanning objective belongs to the imaging difference system with a small aperture, which requires rather high optical resolution.

2.Because of a photoelectric device, it should not only adjust the aberration of white light (mixed light), but consider aberrations of three independent wavelengths of R, G and B.

3. To correct the distortion aberration.

Sino-Galvo Tech. has practical experience in optical galvanometer scanner and its control framework's R&D, creation and deals. Our self-created laser cleaning framework has no harm to the substrate, can meet long-term activity of high force laser cleaning, and can be coordinated with different sorts of lasers.

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