For as big, bulky, and power-hungry as they were, CRTs were an analog joy of the early days of TV, video games, and computers. The crackling high-voltage, the occasional whiff of ozone, the whizzing electrons lancing through a vacuum to excite a phosphorescent image — by comparison, thin-film LCDs are sterile and boring.

Sadly, CRTs are getting harder to come by these days, and at the extreme ends of the size spectrum, may never have been available at all. Thankfully, if your project demands a retro CRT look, fitting your LCD with a custom lens might just do the trick. The link leads to the first article in a series by [jamhamster] on the travails of lensmaking, which even when not practiced for precision lens production can still be tricky. After going through the basics of material selection — acrylic, but not cold-formed, please; such sheets have internal stresses that tend to express themselves as cracks while grinding. The grinding method is as ingenious as it is simple: a blank is fitted to a flat arbor and ground down by spinning it against a belt sander, on the side without the platen. A little WD40 for lubrication and thermal management helped while progressing to finer grit belts, with a final treatment using plastic polish yielded a shape very reminiscent of an old CRT face. There’s a Twitter video that shows the simulated CRT.

Further installments of the series detail the optical properties of these lenses,  options for bonding them to an LCD, and tying all the steps into a coherent method. We think the results speak for themselves, and suspect that these “emulated” CRTs often draw a double-take.

Thanks to [John] for the tip.

Acrylic easily scratches, cracks, and will haze when exposed to UV. Original CRT glass works best. There’s still an abundance of dead TV’s being thrown away. Of course there’s environmental and safety issues, but the results are convincing.

https://www.youtube.com/watch?v=-mMaO6ULuSk

Search “crt aquarium” for the howto:

Gently try not to give yourself a heart attack when the tube implodes. Those things have a habit of embedding little razorblade like shards of glass into everything within a twenty foot radius and waking up the neighborhood in the process. Granted the end result looks good. There are safe-ish ways to repressurize tubes but get it wrong and boom. Note, putting it in a confined space and then setting it off from a distance with a long length of string, although feasible, probobly safer and definitely exciting is somewhat messy.

Throw a blanket over it and hit it with a hammer. Fears about imploding/exploding are blown way out of proportion to the actual danger.

Have done just this on a 32 inch best. It amazes me how much energy is stored in the vacum inside the tube. It also amazed me how strong the tube was… i hit it numerous times with a hammer and it did not care. Of course initially i was very afraid of the implosion so i was rather light on my taps. I am certain that without the bed sheet i used, i would still be finding glass shards…

can confirm. my friend and i spent an afternoon slowly working up our nerve to breaking a tube and when it went it was a non-event. i assume there’s a rare worst case that is surprising but generally it’s a pretty controlled event and there won’t even be any ejecta to catch.

Just grab one of the pins on the tube end with some pliers and twist it off until the glass cracks a little, then wait until the hissing stops.

I’ve ruined more CRTs than I’ve salvaged because getting them out of the sockets without bending the pins and cracking the glass is so difficult.

When I worked in TV shops many years ago we had to dispose of CRTs. At the center of the end of the neck there’s a little glass nipple that was used to evacuate the tube, before being fused shut. On some older tubes you have to remove a plastic cap to get to it. Just take some pliers and snap this nipple to let air in safely. Some of us wrapped the tube in a blanket first, others thought that that wasn’t manly enough. I never saw one implode.

Thanks, that’s a really good tip.

That was a very good nipple

That little nipple was where most got ruined when removing the socket connection, I ruined a few myself in repair shop, even had to bite the cost of replacing a couple tubes of customers in house while working on those sets back in the day. As far as imploding, yep, hit one sharp enough in the thin neck before the vacuum bleeds down and they will definitely do so, makes a fairly odd sound like a hollow thump and they will send frag out when the pressure wave rebounds, there is also that sound of normal breaking glass, not just like a window but like a large bottle. It gets muffled some from the vacuum pulling that sound inside the tube. Most of the time the tubes were getting somewhat dim and needed rejuvenated which was the main reason for having to mess with the socket in the first place. I had a tube restorer back then and it did a fair job of cleaning up the cathodes and getting a better picture but there were always the ones that were just too far gone and would just stop working completely or not improve. Sometimes the tester/restorer would tell me the electron gun emissions were back in spec but the image didn’t back that up. I had a special tool for venting tubes that were sent back to a reman. shop back then too. It would make a small cut on the neck, some tubes had core charges on them.

If you put the acrylic in the oven at close to the glass temperature, the internal stresses will dissipate too.

What if you make a clay model of the lens and then vacuum form the lens from acrylic? Thinner material can be used. Not to mention no need for grading, sanding and polishing.

Sure, you can form it on a mould, but then one surface has the imperfections of the mould surface, the other is smoother and more or less equidistant from the mould. That will distort the view a little, but will not act as a lens very much. It is simpler though, that can be good.

Isn’t that mostly what DSLR lens manufacturers call molded aspherical lenses

If your CRT makes you smell ozone that’s what’s techically called “a problem”.

A little ozone is very good to have in an indoor environment, especially one with no fresh air entering from the outside which itself contains ozone.

Personally I love the smell of ozone.

…in the morning!” FTFY B^)

I really don’t understand why there is nostalgia for this stuff, between the leaded glass and the high voltages and the high energy electron beams. Is there also nostalgia for open pit toilets? Maybe we can bring back cholera and smallpox for their nostalgia value.

I do like the occasional pit toilet now and then.

C’mon, though. Look at the thing. It’s so beautiful.

You really just equated sanitation issues and infectious diseases with crts lol? Hyperbole much? In all seriousness though I’m sure others are just as horrified by what you are nostalgic about as you are with crts. After all, one man’s trash is another man’s treasure, so unless you want to be judged for your passions I’d suggest not being so hasty to judge others.

You must be fun at parties.

Why would you NOT want to have a high voltage power supply and a high-energy electron beam in your builds? Next you’ll tell me you don’t want a continuous wave laser that can etch glass.

While jamhamster’s complaint seems to have been corrected by the time I’m reading the article (at least, I see a link to his blog) I don’t see the usual mention of his tag anywhere in the text for those who don’t click on the link. Attribution is important on the internet and making people WORK to find out who did a thing can be almost as bad as not giving attribution in these days of short attention span.

Thanks, the main issue is ripping and reposting the video from here: https://twitter.com/RealJamHamster/status/1337329824210227200 I mostly post updates on Twitter for my projects and rarely update the blog so this is the best way for people to reach me if they have questions about the things I’ve made. :-)

FYI, Some of us HaD readers are put off by links to social media sites (e.g. Fakebook, I’mgroot, Y’alltubby, etc.)

so, don’t click ‘m. Proper attribution is important, there is a lot of work in these projects.

That’s the big question, does an author get to dictate exactly how their work gets attributed (whether a specific link to their social media, using their full name, using their account handle, what would be sufficient)? I get jamhamster wants to get ad/view revenue for the work he put in, no argument there, but making it look like hackaday purposely didn’t link his SM in an attempt to subvert his earning is disingenuous. They likely had no idea jamhamster had the video monetized and sure it would’ve been smart for the article author to reach out to double check before posting, but it’s nowhere near negligent to have not done so.

This might produce a better result if coupled with CRT shaders. If I had to choose between a lens and shaders, I would say shaders are superior and easier to use (although you do need more processing power — more than is required to just run an old game).

I’d like to see a video showing that display playing games using the CRT Guest Dr. Venom or other CRT shaders.

Lenses on your screen? You speak of retro lenses? How about what Terry Gilliam did in his 1985 movie _Brazil_. Imagine a vast steampunk clerical office, with all the size and soul of Office Space but without the walls between cubicles, and all the workers are hunched over electromechanical workstations, where the only concession to ergonomics is a distorting Fresnel lens, which magnifies, yes, a CRT. I can’t paste a picture here but here’s one I found with a DDG search for “brazil movie magnifier”. https://static01.nyt.com/images/2019/01/25/arts/25BRAZIL/25BRAZIL-facebookJumbo.jpg

Yeah, Terry Gilliam has quite a sense of aesthetics, gotta love it. Also check out the following picture from the 1984 movie, not a great movie but I think the designers had seen Gilliam’s work.

https://s3.amazonaws.com/criterion-production/editorial_content_posts/hero/6507-/K4QBwAjpL43nwcgwEHjaAPEfNc85oZ_small.jpg

If you really want the look, the sides as well as the corners must be curved on 2 separate radii. Think arch holding out one atmosphere made of glass. You will then have to “underscan'” your text over less of the LCD. That look was copied all across mid century design and art. Only late in the CRT era did flatness and straight sides happen on smaller and bolder tubes. Sony trinitron tubes had a cylindrical face, you might get a LCD to bend that way.

Beautiful things. I’d love to be able to buy some. For a similar effect I have used old stage spot lenses fitted to the front speaker hole of a bakelite radio case containing an LCD display. Not in this league for finish though.

OMG, I want that as a screen protector on my phone:)

With luck, none of your projects will ever show up on Hackaday again. From your complaining, seems that would be best for all involved.

Love Hultèn (the guy who did the chattering teeth synth) recently posted a video on his MDLR-37 fold-up synthesizer — set into one of the wooden face plates is a round lens magnifying a digital oscilloscope, and it looks gorgeous.

https://www.lovehulten.com/mdlr37.html

This is kind of complaining that the free meal you got isn’t vegetarian. Be thankful that it was freely given.

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