In order to provide eye care to the millions of people around the world in need of proper vision correction, an inexpensive method is needed to diagnose and produce accurate and dependable eye glasses.
What are the projects?
A Bucknell University senior design team developed a low-cost, precise diagnostic tool for measuring the prescriptions needed to create corrective eye glasses. The project was very successful. The tool is easy to make, easy to use, and very inexpensive compared to an optometrist grade diagnostic array. ProSEC’s diagnostic tool resembles a small telescope and costs less than $20. The perceptions read are also relatively accurate, with the error less than noticeable to the human eye. (Pictures will be posted later to show the device and how it is used.)
In order to produce a pair of eyeglasses at low cost, a method is required for developing lenses of the prescribed dimensions. After the lenses are produced, they can be fitted into the frame style chosen. Currently, the project goal is to process (cut and bevel) lenses with high accuracy and precision in order fit those lenses into the corresponding frames. Polycarbonate, preformed lens blanks of various prescriptions are used as the basis for the eyeglass lenses. ProSEC’s lens processing device cuts this blank down to the rough size and shape needed for the frame. Once the lens is shaped, a beveling process is used to double bevel the edge of the lens. The frame has the reverse bevel shape on its inner contour; therefore the bevel provides a means for the frame to secure the lens properly. Once the bevel is formed, a process of finishing is needed to properly fit the slightly oversized lens into the frame. This step requires manually sanding the edge of the lens, little by little, until it can be secured into the frame. Once the frame is known to fit, the sanded edge is polished for styling purposes. We hope to produce eyeglasses for under $10 a pair, using purchased lens blanks, the ProSEC processing device, and purchased frames.
ProSEC LPD: Lens Processing Device
The LPD cuts the lens blank to a desired frame shape. The tool’s central component is an adapted router and fabricated router table. The wooden router platform consists 3 major components; workspace, router support, adjustable shaping guard.The workspace is just a large piece of wood, used for movement of the lens during processing and support of the router platform. The router platform is located at one end of the workspace. This platform is of a height necessary to make proper cuts with a mounted trim router. The platform also has enclosed areas for containing dust and debris produced during processing. A 1/4” trim router is mounted on the router platform vertically, so that the router bit is beneath the platform top, about an inch above the workspace. The shaping guard is a small rectangular shaped piece of wood, which is adjustable as needed. In general, this guard is set in place so that the front edge is inline with the front edge of the router bit. The template used in the coupling block contacts this guard to shape the lens and prevent too much material from being removed. Basically, the coupling block is a machined cube used to hold the lens blank and template concentrically with blocking tape. This coupling block is secured in a tool to provide two handed control and safety to the operator. Each of the ProSEC devices are used in conjunction, in an outline process to produce affordable and accurate eye care solutions.