Everything You Always Wanted To Know About Radioactive Lenses

We think of radioactive material as something buried away in bunkers with bombs, power plants, and maybe some exotic medical equipment. But turns out, there are little bits of radiation in the water, our soil, bananas, granite countertops, smoke detectors, and even some camera lenses. Camera lenses? A few decades ago, camera companies added rare elements like thorium to their glass to change the optical properties in desirable ways. The downside? Well, it made the lenses somewhat radioactive.  A post by [lenslegend] explains it all.

Exotic elements such as Thorium, Lanthanum and Zirconium are added to glass mixtures to create the high refractive indexes necessary in sophisticated lens designs. Selection of premium quantities of glass from the large glass pots, stringent spectrophotometric tests after stress and strain checks provide the valuable raw glass for ultimate use in lens elements.
Konica Hexanon Lens Guide, Konica Camera Company, 1972

According to [lenslegend] the practice started in 1945 with Kodak. However, by the 1980s, consumer distaste for radioactive things and concern for factory workers ended the production of hot camera lenses.

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Tiny Tesla Valves Etched In Glass

While it’s in vogue right now to name fancy new technology after Tesla, the actual inventor had plenty of his own creations that would come to bear his namesake, including Tesla coils, Tesla oscillators, Tesla turbines and even the infamous Tesla tower. One of the lesser known inventions of his is the Tesla valve, a check valve that allows flow in one direction without any moving parts, and [Huygens Optics] shows us a method of etching tiny versions of these valves into glass.

The build starts out with a fairly lengthy warning, which is standard practice when working with hydroflouric acid. The acid is needed to actually perform the etching, but it’s much more complicated than a typical etch due to the small size of the Tesla valves. He starts by mixing a buffered oxide etch, a mix of the hydroflouric acid, ammonia, and hydrochloric acid, which gives a much more even etching than any single acid alone. Similar to etching PCBs, a protective mask is needed to ensure that the etch only occurs where it’s needed. For that there are several options, each with their own benefits and downsides, but in the end [Huygens Optics] ends up with one of the smallest Tesla valves ever produced.

In fact, the valves are so small that they can only be seen with the aid of a microscope. While viewing them under the microscope he was able to test with a small drop of water to confirm that they do work as intended. And, while the valves that he is creating in this build are designed to work on liquids, [Huygens Optics] notes that the reason for making them this small was to make tiny optical components which they are known for.

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Injection-Molded Glass Breakthrough Shatters Ceiling Of Work Methods

Glass is one of humanity’s oldest materials, and it is still used widely for everything from drinking vessels and packaging to optics and communications. Unfortunately, the methods for working with glass are stuck in the past. Most methods require a lot of high heat in the range of 1500 °C to 2000 °C, and they’re all limited in the complexity of shapes that can be made.

As far as making shapes goes, glass can be blown and molten glass pressed into molds. Glass can also be ground, etched, or cast in a kiln. Glass would be fantastic for many applications if it weren’t for the whole limited geometry thing. Because of the limitations of forming glass, some optic lenses are made with polymers, even though glass has better optical characteristics.

Ideally, glass could be injection molded like plastic. The benefits of this would be twofold: more intricate shapes would be possible, and they would have a much faster manufacturing time. Well, the wait is over. Researchers at Germany’s University of Freiburg have figured out a way to apply injection molding to glass. And it’s not just any glass — they’ve made highly-quality, transparent fused quartz glass, and they did it at lower temperatures than traditional methods. The team used x-ray diffraction to verify that the glass is amorphous and free of crystals, and were able to confirm its optical transparency three ways — light microscopy, UV-visible, and infrared measurements. All it revealed was a tiny bit of dust, which is to be expected outside of a clean room.

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Micromachining Glass With A Laser — Very, Very Slowly

When it comes to machining, the material that springs to mind is likely to be aluminum, steel, or plastic. We don’t necessarily think of glass as a material suitable for machining, at least not in the chuck-it-up-in-the-lathe sense. But glass is a material that needs to be shaped, too, and there are a bunch of different ways to accomplish that. Few, though, are as interesting as micromachining glass with laser-induced plasma bubbles. (Video, embedded below.)

The video below is from [Zachary Tong]. It runs a bit on the longish side, but we found it just chock full of information. The process, formally known as “laser-induced backside wet-etching,” uses a laser to blast away at a tank of copper sulfate. When a piece of glass is suspended on the surface of the solution and the laser is focused through the glass from the top, some interesting things happen.

The first pulse of the laser vaporizes the solution and decomposes the copper sulfate. Copper adsorbs onto the glass surface inside the protective vapor bubble, which lasts long enough for a second laser pulse to come along. That pulse heats up the adsorbed copper and the vapor in the original bubble, enough to melt a tiny bit of the glass. As the process is repeated, small features are slowly etched into the underside of the glass. [Zachary] demonstrates all this in the video, as well as what can go wrong when the settings are a bit off. There’s also some great high-speed footage of the process that’s worth the price of admission alone.

We doubt this process will be a mainstream method anytime soon, not least because it requires a 50-Watt Nd:YAG fiber laser. But it’s an interesting process that reminds us of [Zachary]’s other laser explorations, like using a laser and Kapton to make graphene supercapacitors.

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The High-Tech Valor Glass Vials Used To Deliver The Coronavirus Vaccine

As the world waits for COVID-19 vaccines, some pharmaceutical companies stand armed and ready with an exciting improvement: better vials to hold the doses. Vials haven’t changed much in the last 100 years, but in 2011, Corning decided to do something about that. They started developing an alternative glass that is able to resist damage and prevent cracks. It’s called Valor glass, and it’s amazingly strong stuff. Think Gorilla glass for the medical industry.

Traditionally, pharmaceutical vials have been made from borosilicate glass, which is the same laboratory-safe material as Corning’s Pyrex. Borosilicate glass gets its strength from the addition of boron. Although borosilicate glass is pretty tough, it comes with some issues. Any type of glass is only as strong as its flaws, and borosilicate glasses are prone to some particularly strength-limiting flaws. Pharmaceutical glass must stand up to extreme temperatures, from the high heat of the vial-making process to the bitterly cold freeze-drying process and storing temperature required by the fragile viral RNA of some COVID-19 vaccines. Let’s take a look at how Valor glass vials tackle these challenges.

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Begin Your Day On An Uplifting Note With A Daily Affirmation Mirror

We’ve seen dozens of “Magic Mirror” builds around here, most of which display all sorts of information — calendar, weather, news. They’re great builds, but they tend to be a bit busy and don’t really inspire a calm start to the day. But if you’re good enough and smart enough, you can build this electronic affirmation mirror, and doggone it, people will like you.

[Becky Stern] stripped the magic mirror concept down to a minimum with this build and uses only an array of 14-segment alphanumeric displays to scroll uplifting messages. The glass she used is partially reflective, and when covered with black tape on the backside, with a small portal for the display, it makes a decent mirror. The displays are driven by a Trinket using static affirmations stored in the sketch; a microcontroller with a WiFi connection could also be used to source affirmations on the fly. Or, you know, stock prices and traffic updates, if you’re not into the whole [Stuart Smalley] thing.

So what about those aforementioned magic mirror builds? We’ve got large ones, small ones, retro ones, and even kid-centric ones. Take your pick!

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Creating Easy Glass Circuit Boards At Home

This tip for creating glass substrate circuit boards at home might hew a bit closer to arts and crafts than the traditional Hackaday post, but the final results of the method demonstrated by [Heliox] in her recent video are simply too gorgeous to ignore. The video is in French, but between YouTube’s attempted automatic translation and the formidable mental powers of our beloved readers, we don’t think it will be too hard for you to follow along after the break.

The short version is that [Heliox] loads her Silhouette Cameo, a computer-controlled cutting machine generally used for paper and vinyl, with a thin sheet of copper adhered to a backing sheet to give it some mechanical strength. With the cutting pressure of the Cameo dialed back, the circuit is cut out of the copper but not the sheet underneath, and the excess can be carefully peeled away.

Using transfer paper, [Heliox] then lifts the copper traces off the sheet and sticks them down to a cut piece of glass. Once it’s been smoothed out and pushed down, she pulls the transfer paper off and the copper is left behind.

From there, it’s just a matter of soldering on the SMD components. To make it a little safer to handle she wet sands the edges of the glass to round them off, but it’s still glass, so we wouldn’t recommend this construction for anything heavy duty. While it might not be the ideal choice for your next build, it certainly does looks fantastic when mounted in a stand and blinking away like [Heliox] shows off at the end.

Ironically, when compared to some of the other methods of making professional looking PCBs at home that we’ve seen over the years, this one might actually be one of the easiest. Who knew?

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