RU198458U1 - F-theta lens for laser scanning system - Google Patents

Abstract

The utility model relates to F-theta objectives for use in stereolithography systems in the short-wavelength part of the optical spectrum. The F-theta lens contains three spherical lenses sequentially located along one optical axis: two positive meniscus and one negative meniscus, and additionally includes a cylindrical lens. The device provides operation in the short-wavelength range while maintaining low distortion and field curvature. 4 ill.

Description

The invention relates to F-theta lenses for use in stereolithography (3D printing) systems in the short-wavelength part of the optical spectrum.

The following F-theta lenses are known [1-3]. The disadvantage of these lenses is the presence of aspherical and toric surfaces, which determines the complexity of manufacturing, the high complexity and high cost of technical implementation for small batches <100 pcs.

Closest to the claimed solution in technical essence is the F-theta laser engraving lens adopted for the prototype [4] (see Figure 1), operating at a wavelength of 1064 nm, having an angular field in the image space of 50 degrees, an effective focal length of 433.3 mm and consisting of 3 optical elements arranged along the optical axis in the order of the optical beam: negative meniscus, positive meniscus and a plano-convex lens or positive meniscus.

The disadvantages of the prototype are that due to diffraction restrictions due to the long focal length, its optimization for work in the short-wavelength part of the optical spectrum is not feasible while maintaining the claimed quality.

The purpose of this utility model is to optimize the prototype for the range 395-415 nm, while maintaining low distortion, field curvature and maximizing the cost of the structure. To do this, in the inventive device:

1. Easily accessible materials of optical glasses are selected that easily satisfy the parameters of impotence and bubbling.

2. The optical surfaces of this F-theta lens are designed so that the lens diameters have sufficiently large optical gaps and easily fit into the lens in bulk.

3. The lens uses only spherical and cylindrical surfaces.

Figure 2 presents a diagram of the inventive F-theta lens. The F-theta lens contains the following elements: two positive menisci, one negative meniscus and a cylindrical lens in the sequence shown in Figure 2.

The main technical data of the claimed F-theta lens

1. The angular field of the object, 2ω = 50 °.

2. The scan size in the image plane, 2y '= 212 mm.

3. The working wavelength, λ = 405 nm.

4. The diameter of the entrance pupil Sp, 5 mm.

The design parameters of the claimed F-theta lens.

Table 1. Lens options.

Figures 2-4 show the results of mathematical modeling.

Consider the compliance of the proposed solutions to the criterion of significant differences.

Difference 1. The lens operates in the short-wave part of the spectrum, in contrast to the prototype operating in the IR spectrum

Difference 2. The lens uses 4 lenses, the layout of the lenses differs from the prototype.

Difference 3. The use of a cylindrical surface in the 4th lens. Therefore, this solution has significant differences.

Literature

[1] Scanning and imaging lens, optical scanning device and image forming apparatus, US6448998.

[2] Optical scanning apparatus and asymmetrical aspheric scanning lens, US 5025268.

[3] Telecentric f-θ lens system for laser COM, US 4880299.

[4] Optical lens, US 20110043931 A1.

Claims (1)

F-theta lens containing three spherical lenses sequentially located along the same optical axis: two positive menisci, one negative meniscus, characterized in that it further includes a cylindrical lens and operates in the short-wavelength optical range.

Images