VFD, LED, and LCD update speeds...

[alank2]

Hi Everyone,

Well, I don't need to ask about LED's because they can switch so fast you can even see it, but I wonder about the update speed of VFD vs LCD.  A LCD datasheet I read said something about a response time of 180ms for on and 100m for off, so taking the max there you can get about an update speed of 5 times per second.  How fast are VFD's?  I looked at a couple of datasheets, but didn't see the speed listed...

Thanks,

Alan

[mariush]

With LCD, it's not the actual panel that's slow, it's the controller. Some can update very fast.  The controller runs at slow frequencies and due to multiplexing pixels, update rate is slow.

I don't have much experience with VFDs.  May want to look at OLED displays, they may update faster.

[bktemp]

You have to distinguish between update speed and response time.
The update speed tells how fast you can write new data to it, like the samplerate of a DAC. The response time is more like the analogue bandwith of the system.

LCDs have a update rate in the range of 60-200Hz. The response time is quite slow and has a strong temperature dependency. It can be as low as a few seconds for low temperatures but is typically in the range of 10ms for tft lcds and 100ms for passive lcds.
Since OLED displays are scanned the same way as lcd screens their update rate is in the same range, but their response time is much faster, typically in the microsecond range.

I have no real values for vfds, but they are quite fast. My guess is somewhere near oleds.

[DanielS]

VFDs will turn on/off as fast as you can drive their voltage up/down, much like LEDs, neon bulbs or plasma displays.

LCDs are so slow compared to emissive display technologies because molecules need to align with the electric field - there is an electromechanical process to their operation. Same goes for e-Ink except the mechanical part is even more acute.