In order to realize laser additive manufacturing and damage repair of complex parts with different sizes, an adjustable variable spot size laser cladding optical system is proposed. The system is an off-axis three-mirror optical system, which is composed of three aspherical reflectors. It can adjust the spot size by moving an asperical mirror with an step motor. It can eliminatesolves the problem of light energy loss fixed spot size of traditional refractive optical systems. The proposed solution is high efficient in complex parts clading process and cost effective. and lift the application limitation of high-power lasers in laser cladding. In this paper, the physical model of off-axis three-mirror optical system is established by means of Zemax software. A 4000 W fiber laser in non-sequence mode was used to simulate the intensity distribution of the spot cross-section. By defocusing, the spot diameter at the working face can change continuously from 6mm to 12mm.
Chromatic confocal point sensors are used to measure the high-precision surface distance, and it's based on the theory of chromatic dispersion and encodes the distance between the measure surface and chromatic lens. By accurately measuring the wavelength value, it indirectly calculates the distance to object surface. The accuracy of the sensor depends on the chromatic range of the lens and the resolution of the spectrograph. It is difficult to design wide measuring range chromatic lens that meanwhile satisfies the high-precision requirement. This paper proposes an optimization method to design high-precision chromatic lens for chromatic confocal point sensors. Firstly, we theoretically study the relationship of the pin-hole diameter and the sensors' performance denoted with the resolution and signal-to-noise ratio(SNR). Then, using the optimization objective FWHM(Full Width at Half Maximum), we build the mathematical model about N.A.(Numerical Aperture), PD(Pupil Diameter) and Δf. Finally, based on the optimization method, we design chromatic lens with Zemax Software, the performance gets the accuracy 2μm in the measure range 1mm.
In recent years, with the increasing demand of intelligent transportation system for large-scale field monitoring, it is a pretty much necessity for the continuous zoom system with large scale ratio and large field angle. Therefore, based on the characteristic of its optical system with 30 times variable ratio and large field angle, the mechanical structure of continuous zoom lens has been designed in detail, and finally two kinds of cam mechanism are described in this paper in order to realize the zoom and focusing process. Furthermore, in order to meet the work environment requirements of video monitoring system for the zoom system, the static simulation and thermal deformation simulation of the key component zoom cam has been analyzed in this paper. The static analysis results show that the deformation of the force of the zoom cam is 0.0015 mm, which can be ignored. Thermal deformation analysis results show that the zoom cam at - 15 °C to 50 °C under the temperature load of maximum deformation is 0.007 mm, which has meet the requirements of the system of working temperature, and all of the above results have verified the rationality of the design of zoom cam mechanism. On the basis of the selective zoom mechanism, a reasonable focusing mechanism is carried out to ensure the focus stability of the focusing mechanism, which can provide the stability of the whole continuous zoom lens system.
This paper proposes a multi-attribute automatic optimization method for lens system design. The method is based on the exploitation of the multi-attribute property of lens systems. Quality attribute and sensitivity attribute of lens system are our main concerns in the proposed method. The quality attribute is considered to characterize the optical performance and the physical constraints of lens system. The sensitivity attribute is perceived as the description of feasibility and practicality in lens manufacturing. Modified coordinate-wise algorithm is employed to perform the optimization of imaging performance as well as specific constraints. The sensitivity attribute is processed to incorporate manufacturing sensitivity into the metrics to evaluate the system more comprehensively by means of minimizing incident and refracted ray angles on optical surfaces. As a result, compromise solutions between quality attribute and sensitivity attribute are obtained. Experiments on two typical lens designs demonstrate the effectiveness of the proposed method.