If you weren’t around (or paying attention) during the early days of flat panel display, you might not be aware of the scourge that dead or stuck pixels represented. These pixels either didn’t light up, were fully lit the whole time, or got stuck on some intermediate color. For those of us coming from CRT monitors, this was a whole new problem that never existed before.
It was so bad that the first thing you did when buying a new screen was load up some special software and spend an hour carefully eyeballing every square inch of the screen to ensure they all worked correctly. If you did find some faulty pixels, you hoped that the warranty policy included coverage for them, and even if you did get a replacement screen, you’re rolling the dice all over again. These days, no one thinks about or checks for dead pixels and finding one is incredibly rare, so what happened?
When Dead Pixels Were a Big Problem
My first personal encounter with an LCD was in the mid- to late- 90s. My dad had a work laptop with a passive color TFT panel, and there was a copy of Disney’s The Lion King game on it that he let me play. That’s a notoriously hard game, but it’s even harder when the entire screen is just one massive smudge when anything moves. You could fill the entire screen with clones of the mouse pointer if you were fast enough.
I only felt comfortable swapping out my last CRT monitor (well, until recently) in the latter half of the 2000s. It was a 900p 19-inch LG monitor, and I regretted it almost instantly, but at least it didn’t have any dead pixels. I wasn’t so lucky on subsequent runs. My entry-level Samsung LCD, which bumped things up to 1080p had a few dead pixels in one corner, and Samsung’s warranty didn’t see that as a defect.
The worst offender, by far, was my launch Sony PSP, which had big clusters of them in various spots, but right in the user manual Sony had written this was “normal” and “part of LCD technology”, so no returns there either.
I also used to see them in schools and at businesses where they had plenty of cheap entry-level LCDs, and that tells you something. Because the lower-end the LCD, the more likely it would have dead pixels and a warranty policy that didn’t see them as a problem.
Those policies were the biggest problem in my opinion, because they were elaborate and borderline unfair. Each manufacturer had these arcane rules about how many dead pixels qualified for a warranty replacement, and then they had to be a certain distance from each other and be in specific parts of the screen, like in the center.
LCD monitors with a coveted “zero tolerance” policy for dead pixels were the most expensive, but it was the only way to guarantee a flawless screen.
Why Dead Pixels Happened
In an LCD panel each pixel is a physical object made up of several components. Every pixel is controlled by a microscopic transistor. If that transistor failed it would mean the pixel was dead and dark, or permanently stuck on white, depending on the specific LCD panel type. If the transistor became locked to a specific state, that’s where you’d see those multicolored stuck pixels.
These defects almost always occur in the factory. LCDs require extremely clean environments and precise manufacturing. At the time the manufacturing methods just weren’t good enough to have a good enough yield of working panels while also throwing out any panel with defective pixels. There are millions of transistors in each panel, and even if you’re 99.9% perfect there will be visible defects. So either these companies had to only sell incredibly expensive zero-defect panels, or just be upfront about the inevitability of dead pixels.
How Display Tech Got Better
So that means it’s actually no mystery why you don’t ever think about dead pixels these days. We simply got better at making screens, but that “simply” is doing a lot of heavy lifting here!
Manufacturers had to make big advances in cleanroom technology and the materials they use. The screens are in ultra-sterile environments while they’re in a vulnerable phase of the manufacturing process. Precision has also increased thanks to robotics and better automation.
The entire manufacturing process has also been refined and made more efficient at every level, over and over again. This means the yields of error-free panels has gone up, making it economically viable to have a zero-tolerance policy for pixel defects, even for budget models. There’s also better fault tolerance in the screens themselves, so even if you have a few dead transistors, it won’t necessarily lead to visible defects.
By the time we were into the middle of the 2010s, dead pixels were pretty uncommon in new screens and all the hand-wringing I used to see on internet forums as people sweated about their new screens having defects just evaporated.
From Pixel Defects to Performance Quirks
While you might still encounter the odd dead or stuck pixel today, it’s not what people worry about when buying a new screen. Oh, no—we have a whole new set of things to worry about. From OLED “burn in” to light bleed and panel uniformity, there are still lots of defects for display nerds to get in a huff about.
Conversations have also moved on to choosing between good image quality and really good image quality. Is the HDR bright enough for you, Sir? Are Sir’s colors sufficiently accurate? Back in 2005, I would have killed for a screen as good as the worst LCD you can buy today, so personally I try to appreciate how mind-blowing the displays I own are, but progress never ceases!
