How long do LCD modules typically last? - Page 1
Forum section: electronics / projects

author: alank2
author_rank: Super Contributor
timestamp: October 30, 2020, 08:39:47 pm
content: So, here are 4 40x4 line ones from buydisplay:https://www.buydisplay.com/character-display/character-display-module?resolution=144Assuming they were used in a low duty cycle, an hour a week or something, how long in years would or could one expect them to operate? 10 years? 20 years? longer?Also, I guess they are all slightly different configurations:tradition dark text on yellow/green - STN Positiveblack text on white - FSTN Positivewhite text on blue - STN Negative Bluewhite text on black - FFSTN NegativeDoes the LCD type have any bearing on longevity as well?Again, not asking about hours of use, but rather of lifetime when used at a low duty cycle.

author: bob91343
author_rank: Super Contributor
timestamp: October 30, 2020, 09:06:44 pm
content: I have a DMM with an LCD that is probably 30 years old and still working fine.

author: mzzj
author_rank: Super Contributor
timestamp: October 30, 2020, 09:23:50 pm
content: 5 to 40+ years depending on your luck.LCD modules seem to fail mostly to contact issues. Running hours to have very little to do with the longevity (except for backlight)

author: alank2
author_rank: Super Contributor
timestamp: October 30, 2020, 09:38:09 pm
content: So from that standpoint are the COG ones more reliable to ones that might have that material between the glass/pcb.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: October 30, 2020, 11:12:39 pm
content: Zebra strips can be a weak point for LCD's, and COG may or may not have those.In dirty or moist environments oxidation can be a problem.My best guess though is that it's a negligible "problem" in most cases.Very cheaply made Chinese stuff is probably less reliable than the more "traditional" made displays.Another failure mode is DC on the glass panel itself. LCD's are always controlled with AC signals, and even low DC offsets of that signal can cause the display to wear out quickly.I once bought a few mains timers with an LCD panel, and they all failed after bout 3 months of use, and I suspect it was because of a DC offset on the LCD. Or maybe, just the chemicals of the LCD were mixed faulty.Once you've found a chinese manufacturer that dares to print a name on it's product you've probably already got a gurantee it's not the cheapest works-for-a-week crap you can get from china. Quality of chinese stuff varies widely.

author: TheMG
author_rank: Frequent Contributor
timestamp: October 31, 2020, 12:12:48 am
content: I would guess the reliability varies with manufacturer and quality, but the well-known brands, as far as simple character/graphic LCD modules go, last a pretty darn long time.Provided no contact issues develop over time, or controller IC failure due to ESD, they last virtually forever. I have seen equipment that has been powered on 24/7 for well over 30 years in which the character LCD module still works perfectly fine, except for the LED backlight which has become very dim, but that's to be expected.

author: amyk
author_rank: Super Contributor
timestamp: October 31, 2020, 12:44:04 am
content: LCD lasts decades, unlike OLED

author: coppice
author_rank: Super Contributor
timestamp: October 31, 2020, 01:04:02 am
content: Quote from: Doctorandus_P on October 30, 2020, 11:12:39 pmI'm not sure what has happened to this issue over the years. It used to be that any drive waveform with a minor imbalance quickly wore out the display. However, these days I see some horrible drive waveforms that don't seem to be causing any trouble. Maybe the liquid crystal has been changed to something more tolerant.

author: amyk
author_rank: Super Contributor
timestamp: October 31, 2020, 02:10:36 am
content: I believe the damage comes from electrolysis --- which can only happen if the LC is conductive, but I guess not all of the ones used today are, yet the industry does not want to take the chance.I'm not sure if Dave's experiment on that is still running:

author: uski
author_rank: Frequent Contributor
timestamp: October 31, 2020, 03:36:32 am
content: It really depends of the environment, powered or not : temperature, humidity levels, frequent environmental changes, vibrations, even chemical contaminants in the air...And it also depends of the quality of the LCD and of its various components, which is unfortunately quite difficult to asses solely from a catalog.In short, it is very difficult to give you an answer with an uncertainty of less than an order of magnitude...What is the context of your question, do you have more information, and what is the lifespan you are trying to achieve ?

author: fordem
author_rank: Regular Contributor
timestamp: October 31, 2020, 01:50:30 pm
content: As mentioned earlier, it's hard to be definitive - early Fluke 8020a displays were plagued with "segment bleed" issues when used in high humidity areas, I bought mine in the summer of 1979, and Fluke sent me replacement LCDs under warranty every year for three years (mind you, the instrument had a one year warranty).In year four they sent me a redesigned display assembly and said it would be the last warranty replacement - that last one is still functional thirty seven years later.

author: alank2
author_rank: Super Contributor
timestamp: October 31, 2020, 04:09:09 pm
content: Quote from: uski on October 31, 2020, 03:36:32 amI just really don't like things that don't stand the test of time. I love old equipment that still works after decades and I hate junk that is dead in 90 days! Realistically a life span of 2 or 3 decades I suppose.

author: Buriedcode
author_rank: Super Contributor
timestamp: October 31, 2020, 07:43:41 pm
content: In the majority of cases, the reason "stuff" doesn't last very long is either because a) it was extremely cheap, if you buy something for stupid money, you can't really expect it to last a life time. And/or b) it wasn't used/stored/treated very well by the user/customer.With equipment or tools that are very old and used by people to claim that "they dont' make them like they used to" - is often survivor bias. It lasted either because it was a particularly expensive/well made tool for its time (whilst the cheaper variants were eventually scrapped), or it hasn't actually been used very much. Not indicative of the quality of manufacture ofallthose types of tools, or for the era. You must remember that these days there is a much greater variation in price-point, with a lot more options. If in the 1970's you could only get one tool, made by one company, for one price, they weren't going to stream line it down to a price point so it lasted only a couple of years.LCD's, in my experience last a very long time, at least two decades. But... the few graphic panels I have from the early to mid 90's have been stored at reasonable temperatures/humidity, and even some of those have LC bleed (those that were once in industrial equipment, that was most likely abused).I cannot comment on the later types, VA, DFSTN/FFSTN, as they are only about a decade old now.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: October 31, 2020, 10:26:42 pm
content: Also surprising in this regard is the UNI-T 210E clamp meter.There are some teardowns of this thing, and it has a shitload of capactiors near the LCD panel.It looks like they had a problem with DC offsets and added series capacitors into each LCD connection.

author: David Hess
author_rank: Super Contributor
timestamp: November 02, 2020, 03:22:55 am
content: If the quality is good, and the LCD is not mistreated, and the LCD is driven correctly, then it should last indefinitely. Other than poor quality, I have seen LCD fail because of excessive temperature from being exposed to the sun, and from fungus eating the polarizer.