I suppose the 7971's used mica for the substrate because it had already been proven in traditional vacuum tubes to be compatible with the manufacturing process.
Panaplex displays seem to use some kind of ceramic material for the cathodes and leads, and then topped with a glass window. It looks like a very complex process, but the results are amazing. On Saturday, September 27, 2025 at 12:00:53 PM UTC-7 newxito wrote: > This looks very promising... looking forward to building a new word clock > with these tubes! > > dudu sa schrieb am Samstag, 27. September 2025 um 18:01:57 UTC+2: > >> About half a year ago, a few friends came to me and asked if I could >> make a Nixie tube similar to the B7971. As one of the few Nixie tube >> manufacturers, I thought about it for a while and decided to give it a try. >> >> I am very grateful to Adam for sending me a B7971 sample—thanks to his >> sample, I was able to accurately measure the filament length, dimensions, >> and other parameters. >> >> [image: 微信图片_20250927232658.jpg] >> >> When disassembling and studying two different models of the B7971, I >> found that it made extensive use of mica sheets as the substrate and some >> pads as connectors to link the cathodes to the pins. This assembly method >> is extremely cumbersome, so I began to wonder if, in 2025, there might be >> new solutions for making the backplate material of the B7971. >> >> >> After a long investigation, I found a very good solution—Rogers >> high-frequency boards. According to the manufacturer’s description, they >> use ceramic material, which allows them to withstand high temperatures. In >> addition, circuits can be printed on the back of the board, eliminating the >> need to make metal strips for connecting the electrodes. It sounded like a >> very promising choice. >> >> So I began designing a solution based on Rogers circuit boards to make >> the B7971, including electrode shapes, routing, and so on. >> >> >> [image: 微信截图_20250927232444.png][image: 微信截图_20250927232503.png] >> >> >> >> If successful, this would be a very good option. To verify the solution, >> I spent a large amount of money on producing Rogers circuit boards. I must >> say, the prototyping cost was really expensive, but there was no other way >> for the sake of R&D. To test this ingenious idea, I had to make a bold >> attempt. >> >> After a long wait, I finally received the package. The moment I got it, >> I felt extremely uneasy. On one hand, I was very excited about this >> solution and hoped it would successfully achieve my goal. On the other >> hand, if it failed, it would mean that all the time and money I had >> invested would be wasted. >> >> The moment I opened it, I was stunned—what the fuck, why is this board >> soft? From my experience, pure ceramics, whether alumina or zirconia, are >> extremely hard materials. How could it possibly bend so easily? Could it be >> that this isn’t pure ceramic? To verify this thought, I decided to test it >> with a hot air gun. >> >> [image: 微信图片_20250927231537.jpg] >> >> Oh no, this was such a huge disappointment—it really wasn’t ceramic. >> Burn marks actually appeared on the circuit board, and at that moment my >> mood hit rock bottom as I began to search for the truth behind it. >> >> It turned out that Rogers boards are a composite material—they are doped >> with ceramics and not pure ceramic. I felt very sad; this perfect solution >> was just rejected like that. >> >> But even so, I didn’t give up. I wanted to try other materials. My idea >> was to skip the baking during evacuation—just vacuum the tube and then fill >> it with gas. Although the impurity content would be high, it would be >> enough to verify whether my electrodes could function properly. >> >> So, I began assembling the electrode materials. I carefully mounted them >> onto the substrate and then used solder wire to connect them to the pins. >> >> [image: 微信图片_20250927234616.jpg] >> >> These are the cathodes used for emitting light made by us, with the >> pins fixed to the back substrate. >> >> [image: 微信图片_20250927231537.jpg][image: 微信图片_20250927234557.jpg][image: >> 微信图片_20250927234551.jpg] >> >> This is what it looks like after assembly. >> >> Next, I connected them to the base. >> >> [image: 微信图片_20250927234600.jpg][image: 微信图片_20250927234603.jpg] >> Everything looked perfect, even if it didn’t seem entirely reasonable. >> Next, I sealed the base with the lamp envelope. >> >> [image: 微信图片_20250927234605.jpg] >> >> >> As it turned out, I was defeated once again. During the sealing >> process, the high temperature of the flame scorched the Rogers circuit >> board. It released a large amount of toxic gases, severely contaminating >> the inner walls of the tube. >> >> [image: 微信图片_20250927234607.jpg] >> >> >> As expected, the seal soon cracked. Due to the release of severe >> contaminants, a large amount of impurities got mixed in while sealing the >> base and the lamp envelope, causing the entire tube to start splitting >> during the cooling process. >> >> [image: 微信图片_20250927234613.jpg][image: 微信图片_20250927234610.jpg] >> >> >> That was the end—this entire approach ended in complete failure. The >> reason can be summarized as insufficient preliminary research; I hadn’t >> fully understood the temperature range of Rogers boards. But even if I had >> known in advance, I think I would still have tried this approach, because >> sometimes the listed range only indicates normal usage and doesn’t >> represent the material’s actual temperature limit. >> >> I’m very sorry to the friends who have been waiting—I know you’ll have to >> wait a little longer. Developing a new Nixie tube is not easy; this is just >> one failed case. However, the problem isn’t insurmountable, and I will >> immediately start working on the next solution. >> >> Finally, I welcome everyone to follow us. We are InixieLab, and I am >> Sadudu, the founder of the lab. Our website is inixielab.com. We are >> currently in stable production of 30mm Nixie tubes, the DGM01 and IN-18s. >> In addition, we are preparing for mass production of the large Z568MAX >> Nixie tube. We have been testing it for over six months, and so far, the >> results are very good. We are already preparing the next batch of materials >> to start small-scale production. >> >> >> >> >> >> >> >> > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion, visit https://groups.google.com/d/msgid/neonixie-l/1c0c9935-b23f-47b1-961d-92a31c5b247en%40googlegroups.com.
