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Product Development Case Study of Safety Glasses

June 11, 2015

By VASILY ROMANOV

DESIGN ENGINEER
 
Tri-Power Design works on a variety of products that can range from a medical device used in a surgery to consumer products such as pet toys. Today we are featuring a product TPD has been working on for one of our clients, Ashwin-Ushas Corporation (http://ashwin-ushas.com/ ). This product is an electrochromic safety sunglasses that has a user operated switch that can take the lens from light to dark in under 2 seconds.
 
Ashwin-Ushas Corporation is a research company founded in 1992. Its research focuses on advanced technologies in the defense, aerospace, space, materials and environmental fields. Its clients include U.S. Department of Defense, U.S. Department of Energy, U.S. NationalAeronautics and Space Administration, U.S. National Institutes of Health (NIH), and many more. (1)
 
Ashwin-Ushas reached out to Tri-Power design to assist them in designing their unique safety glasses. The special component of the design is the electronically controlled tint technology developed by Ashwin-Ushas. It is based on unique patented dual-polymer (“complimentary-polymer”) Conducting Polymer electrochromic system. This system, paired with a unique patented applied-voltage algorithm, reduces the switching time from light to dark (and dark to light) to less than 2 seconds. This technology also allows these glasses to work in virtually any environment, and has been tested up to 10,000 switches without observable degradation(2). These achievements directly compete with standard photochromic technology (also known as “Transitions® lenses” and address its typical pitfalls such as long switching times(3), limited life span(4), and inability to work inside of a car(5).
 
Tri-Power’s challenge in this project was to engineer / develop eyeglass frames to package Ashwin-Ushas technology unique technology. The project was approached in a standard phased manner:
 
1. Phase 1 – Concept
Tri-Power worked with an industrial designer to derive a frame shape that would be both aesthetically pleasing, as well as provide the space required technology mentioned above. At this stage, the CAD models created was a single solid form.
 
  
Figure 1, Safety sunglasses prototype with prescription insert: bare sunglasses(2)
 
2. Phase 2 – Product Design
Final concept from Phase 1 was broken apart into an assembly of sub-components. During this process, TPD focused on how each component went together and began to work out the details of how the electronics developed by Ashwin-Ushas would be packaged. Additionally, the overall manufacturability of the parts is engineered in.
 
3. Phase 3 – Prototype and Testing
During this phase, Ashwin-Ushas began to work with their PCB vendor to create prototypes of the PCB’s that would be packaged into the frames. Concurrently, TPD created prototypes to house the electronics using both rapid and conventional machining methods.
 
 
Figure 2, Safety sunglasses prototype with prescription insert: schematic(2)
 
Phase 4 – Final Design
After multiple prototype iterations, Tri-Power began to review all of the assembly components and prepare them for tooling and manufacture. Material selection is also completed during this phase. Once completed, several sets of “Pre-Production” prototypes were made using production materials.
 

 Figure 3Ashwin electrochromic sunglasses prototype(2)

Phase 5 – Production Engineering

This step is one of the most important, and is the current state of this the project. At this time, both TPD and Ashwin-Ushas are closely reviewing the preproduction prototypes, and are making final tweaks and adjustments to both electronics and injection molded parts. After all changes are completed, a final round of production like prototypes will be made for verification. Finally, a documentation package including part and assembly drawings with BOM will be finalized to be forwarded to production manufacture.

Upon completion of Phase 5, the project will move into “short run” manufacturing where the first round of production parts are made. TPD will also begin working as a liaison with the manufacturers to ensure all necessary guidelines are followed for this product. After “first shots” are approved, the safety frames will begin their life as a mass produced product.

That is how a typical product development cycle is carried out. This experience is one of the most sacred for a product development engineer, and a successful project completion is what every product engineer strives for. What comes next is a start of another project and another round of new challenges, and we always look forward to a new challenge. So let us know if we can help you with your future projects by contacting us through our website at tripowerdesign.com/contact/
 
1.     “About Us”, Ashwin-Ushas Corp, Retrieved 28th May 2015, http://ashwin-ushas.com/about-us/
 
2.     “ Electrochromic Sunglasses & Goggles”, Ashwin-Ushas Corp, Retrieved 29 May 2015. http://ashwin-ushas.com/electrochromic-sunglasses-goggles/#technology
 
3.     Heiting, Gary. "Photochromic Lenses: Transitions and Other Light-Adaptive Lenses." Access Media Group LLC, Retrieved 28 May 2015. http://www.allaboutvision.com/lenses/photochromic.htm
 
4.     “Frequently Asked Questions”, X-Cel Optical Company, Retrieved 28th May 2015. http://www.x-celoptical.com/faq.php
 
5.   Franken, Leo. “Pros VS Cons of Transition Lenses”,  Spectacle Shoppe, Retrieved 28th May 2015, http://www.spectacleshoppe.ca/blogs/news/10474153-pros-vs-cons-of-transition-lenses