What is a laser focusing lens？

1.Scan range.

The larger the area that the lens can scan, the more popular it is of course. But if you blindly increase the scanning area, it will bring a lot of problems. Such as the light spot becomes thicker, the distortion increases and so on.

2. Focal length (has a certain relationship with working distance, but not equal to working distance).

a. The scanning range is proportional to the focal length of the field lens-an increase in the scanning range will inevitably lead to an increase in the working distance. The lengthening of the working distance will inevitably lead to the loss of laser energy.

b. The diameter of the focused spot is proportional to the focal length. This means that when the scanning area reaches a certain level, the obtained spot diameter is very large, that is to say, the laser power density drops very quickly (the power density is inversely proportional to the 2nd power of the spot diameter). Conducive to processing.

c. Since the F-Theta field lens uses the relationship of y'=f*θ to work, the actual values of θ and tgθ are still different. And as the focal length f increases, the degree of distortion will increase.

3. Working wavelength.

At present, most of the ones used on the market are 1064nm and 10600nm. However, with the development of later lasers, 532nm, 355nm and 266nm field lenses will also have corresponding applications.

Focusing mirror for laser marking machine

In monochromatic light imaging, the image surface is a flat surface, and the image quality of the entire image surface is consistent, with small aberrations and no vignetting. For a certain incident light deflection speed corresponds to a certain scanning speed, so the linear scanning can be realized with the incident light of equal angular velocity. The deflection position of the incident beam is generally placed at the front focal point of the object space, and the chief ray of the image side is parallel to the optical axis, which can achieve consistent on-axis and off-axis image quality to a large extent, and improve the uniformity of illumination. It is widely used in lasers. Mark system

In the marking system, after the laser beam passes through the focusing lens system, off-axis deflection will occur. Relative to an ideal plane, abnormal images or distortion will appear on the marking surface. The focusing lens is a professional lens system whose purpose is to form a uniform focused spot of the laser beam in the entire marking plane. It is one of the most important parts of the laser marking machine. In the absence of deformation, the position of the focus point depends on the focal length of the lens and the tangent of the deflection angle, and the position of the focus point only depends on the focal length and the deflection angle, which simplifies the calculation method of focus positioning.