Optimization of Zoom Lens with Discrete State of Liquid Lens Elements by Using Genetic Algorithm

This paper is to employ liquid lens elements to design a lens with zoom function by using the genetic algorithm (GA) optimization. The liquid lens elements used in the proposal can apply voltage adjustment to generate the electrical field that induces the liquid with electric conductivity to vary the surface curvature between two different kinds of liquids. According to the voltage level, the liquid lens element makes the discrete variation of the curvature and thickness realize the zoom function without moving the lens groups so that the overall length can be reduced. However, it is difficult to design the zoom lens under the discrete variation of the curvature and thickness in the liquid lens elements and the mechanical space that is constantly limited. The GA offers a flexible way for lens optimization. We regarded the spot size as the fitness function to look for the optimum curvatures, thickness, and the corresponding statuses of liquid lens elements for the zoom lens. As a result, the zoom lens with constant space can be realized by running the selection, crossover, and mutation operation in the GA optimization.

Line Beam Shaper for Intra-Oral Scanning Device

This paper describes an optical system as the line beam shaper for an intra-oral scanning device. The line beam shaper needs to provide desired beam quality, including bean length, uniformity, line width and depth of focus while maintaining compact form factor. More specifically, the proposed optical system was demonstrated to use only the on-the-shelf lens element to resolve all the optical performance issue, and to lead to a versatile solution for varied specification.

Diffractive Optical Elements with a Large Angle of Operation Recorded in Acrylamide Based Photopolymer on Flexible Substrates

A holographic device characterised by a large angular range of operation is under development. The aim of this study is to increase the angular working range of the diffractive lens by stacking three layers of high efficiency optical elements on top of each other so that light is collected (and focussed) from a broader range of angles. The angular range of each individual lens element is important, and work has already been done in an acrylamide-based photosensitive polymer to broaden the angular range of individual elements using holographic recording at a low spatial frequency. This paper reports new results on the angular selectivity of stacked diffractive lenses. A working range of 12° is achieved. The diffractive focussing elements were recorded holographically with a central spatial frequency of 300 l/mm using exposure energy of 60 mJ/cm2at a range of recording angles. At this spatial frequency with layers of thickness 50 ± 5 µm, a diffraction efficiency of 80% and 50% was achieved in the single lens element and combined device, respectively. The optical recording process and the properties of the multilayer structure are described and discussed. Holographic recording of a single lens element is also successfully demonstrated on a flexible glass substrate (Corning(R) Willow(R) Glass) for the first time.

A Path Planning Approach for Wedge/Aspheric Lens Element Grinding Based on Space Coordinate Transformation

Wedge/aspheric lens element is a combination of wedge prism and aspheric lens as a single piece component forming a decentred lens, which plays an important role in the fields of liquid crystal projection display, laser fusion, high-energy laser, satellite optical system and large astronomical telescope, etc. Wedge/aspheric lens element are primarily manufactured by CNC machining, especially 3-axis CNC grinding. This paper presents a facile tool path generation approach based on space coordinate transformation. The proposed method can be used to improve and automate three-axis Wedge/aspheric lens element machining for CAD/CAM systems. As part of the validation process, the tool paths generated are analyzed to compare with the desired part.

An Adaptive Tool Path Generation for Large Scale Wedge/Aspheric Lens Element Grinding Based on Isophote Interpolation

Large scale wedge/aspheric lens element is a combination of wedge prism and aspheric lens as a single piece component forming a decentred lens, which is primarily manufactured by Computerized Numerical Control (CNC) machining, especially 3-axis CNC grinding. This paper presents an efficient tool path generation approach based on isophote interpolation. The interpolation guarantees that interpolated points always stay on the iso-inclination curve of the parametric surface. This symmetry ensures that the method can improve and automate large scale wedge/aspheric lens element machining for 3-axis CAD/CAM systems. As part of the validation process, the tool paths generated are analyzed and compare with the desired part.