Death by Moisture? How to Overcome this Endoscope Challenge

Autoclavability is an important aspect to consider when designing a scope, regardless of whether it’s robotic or traditional, for that matter. Endoscope manufacturers challenge themselves to design reusable endoscopes to withstand more autoclave cycles, striving to extend their lifetime and thus reducing their lifetime costs.  

As you know, we designed our SCHOTT PURAVIS® glass fibers to be robust and long-lasting for optical transmission, but we are fully aware that there are delicate components around our fiber bundle inside the scope that need protection. Optical elements, cameras, and other electronics also fight for the limited space inside the scope handle.

One of the biggest concerns of endoscope makers is moisture getting inside the scope during autoclaving, eventually causing the scope to fail. This moisture could enter through the distal window, electronic or power connections, or even creep up the inside of the flexible cable connecting the scope to the control equipment. The real challenge then becomes: how do you protect the scope from damage in a smart way to keep performance high and the scope’s diameter small?

Protecting the Inside of the Scope

We are in a great position to bring all necessary competencies to the table. We collaborate with internal colleagues from our Electronic Packaging division who have hermetic sealing expertise. Their know-how allows us to design in hermetic feedthroughs that transmit light, images, or electrical signals without allowing moisture into the scope.

Let’s look at this in more detail. At the distal end of the scope, we can provide a hermetically sealed window for imaging. Sapphire is the most common window material due to its toughness and optical transmission, but there are other options available. At the proximal end of the scope handle, we can design a transition plate which isolates the inside of the scope handle from the cable assembly. It would contain hermetic electrical feedthroughs for power and data signals as well as a transition tube that allows us to mechanically fix the bundle and robustly seal in and around the fibers. We developed this redundant fiber sealing system to drastically reduce moisture diffusion through the fibers during the autoclave process.

Protecting the Scope-Tower-Connection

Now, let’s look at the harness connecting the tower to the scope. It includes the individualized power, data, and light cables that need to be connected to the power system, control computer, and the light engine. Because this cable harness is attached to the scope, it also sees the full autoclave cycle. Instead of terminating these cables with normal polymer connectors, you may want to consider hermetically sealed connectors to provide a redundant moisture barrier that can drive up the lifecycle of the product.

So, how does working hand-in-hand with our Electronic Packaging group help keep the scope’s diameter small? By working closely with both our customers and our internal teams, we can quickly evaluate the space vs. sealing tradeoffs for various solutions and move forward with the best path.

Experience with these details is a game changer. Collaboration is key, not only with you to evolve scope designs, but also internally at SCHOTT. Our teams work together very closely on improving the lifetime of a scope. Why not join us as we explore these possibilities! We look forward to hearing from you.