The main characteristic of adaptive lenses is to change their shape, and consequently their focal length, by modifying their physical parameters. On the other hand, Fresnel lenses have such features as large aperture, short focal length, they are slim and reduced in size. This kind of lenses have become very popular due their applications, such as in compound eyes, optical communication systems, photolithography, imaging systems, etc. Nowadays, several kinds of tunable lenses exist such as those made with dielectric materials, lenses that change their focal length by varying the refractive index of the material, liquid lenses composed by elastic membranes and solid elastic lenses. In this work, we present the design, simulation of the mechanical behavior using Finite Element Method (FEM) and cost analysis of an Adaptive Fresnel Lens made of an elastic material, together a mechanical mounting system. Our study considered the use of design thinking methodology to obtain the best optical design at minimal cost. Analysis, results and future applications are presented.
The cornea contributes substantially to the performance of the human eye and obtaining the shape of the anterior corneal surface is crucial for ophthalmic applications such as the manufacture of contact lenses and visual laser correction. In this direction, there exist a large amount of theoretical models which describe the shape of the anterior corneal surface. A model of the anterior corneal surface using high-order aspherics has been previously reported in the literature, and one of the main features of this model is that it has been shown to accurately reproduce the clinical data. In this work we have designed a refractive surface with variable asphericity adopting the model mentioned above by means of finite-element software, and once the design was obtained we proceeded to manufacture the optical surface made of a polymer known as PDMS. Also, an interferometric analysis with a Mach-Zehnder interferometer was performed in order to obtain its wavefront aberration function. The main application of this optical surface is to be used as a substitute of a corneal surface within an optomechanical system to mimic the performance of the human eye.
Tunable lenses are optical systems that have attracted much attention due to their potential applications in such areas like ophthalmology, machine vision, microscopy and laser processing. In recent years we have been working in the analysis and performance of a liquid-filled variable focal length lens, this is a lens that can modify its focal length by changing the amount of water within it. Nowadays we extend our study to a particular adaptive lens known as solid elastic lens (SEL) that it is formed by an elastic main body made of Polydimethylsiloxane (PDMS Sylgard 184). In this work, we present the design, simulation and analysis of an adaptive solid elastic lens that in principle imitates the accommodation process of the crystalline lens in the human eye. For this work, we have adopted the parameters of the schematic eye model developed in 1985 by Navarro et al.; this model represents the anatomy of the eye as close as possible to reality by predicting an acceptable and accurate quantity of spherical and chromatic aberrations without any shape fitting. An opto-mechanical analysis of the accommodation process of the adaptive lens is presented, by simulating a certain amount of radial force applied onto the SEL using the finite element method with the commercial software SolidWorks®. We also present ray-trace diagrams of the simulated compression process of the adaptive lens using the commercial software OSLO®.
Tunable liquid-filled lens (TLFL) is a lens that changing their focal length by modify the quantity of
liquid within the mount. Recent research shows that, the use of tunables lens makes lighter, simpler and
more compact optical devices in micro-ingineering. In the literature there are papers that present
simulations of the behavior of tunable micro-lenses composed slim membranes. We use a TLFL
composed a cylindrical metallic mount with a compartment for two transparent elastic membranes filled
with water between them. Membranes with plane, spherical and conic surfaces are employed. The
membranes are elaborated of Polydimethilsolixane and the mechanical mount is made of alluminium. In
this work, we present the opto-mechanical design, analysis and simulations of behavior de tunable liquid-filled
lenses composed thick membranes. The analysis is made in three TLFL with different types
membranes. The simulations and analysis of mechanical behavior were made with SolidWork™ software.
Moreover an application with genetic algorithms was development to obtain the geometrical parameters
of the lenses when a value of pressure is applied on the membrane surfaces. On the order hand, the
analysis of optical behavior of the lenses was made with the OSLO software. Finaly, results are shown.
In this work, we present the optical design of a tunable focus liquid lens composed with meniscus
surfaces. The surfaces are elaborated of PDMS. Analysis of the opto-mechanical behavior of the lens is
presented.
Recent times have seen the production of normal and micro liquid lenses with variable focal length. These have been
specially made with transparent elastic materials and liquid medium between them, or with a dielectric liquid medium
inside the cavity. Change in the volume of the liquid medium, in the first case, or the application of an electric field as in
the second, produced a change in the optical parameters of the lens. The present study offers the opto-mechanical design,
manufacture and characterization of a solid elastic lens made of Polydimethylsiloxane (PDMS). To do so, we have
prepared a mechanical support frame to hold all of the components of the lens and also allow for the application of radial
stress on its periphery. In order to ensure a well-finished lens surface a high quality optical glass mold has also been
constructed. Finally, we will present an analysis of the properties of this type of lens when it undergoes variations of
radial stress. The experimental results are presented.
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