Digital vs Analog TFT LCDs

Telek · 11-07-2001, 04:15 AM

OK, I tried to do a little searching but I can't seem to find anything on this specific topic.

I want to put an LCD in my car, however I don't know if I should shell out the extra for a true digital LCD or just use an analog one that plugs into a normal VGA port on your computer.

Can anyone give me some advice? Like for example, what do you guys all use? What size is it? Where is it mounted (and how far away from your eyes is it normally)? What do you use it for? Is text easily readable on it?

I want to have a touchscreen display that I can easily read text on. 640x480 is a little small but getting anything bigger than that I think will be difficult (read: $$$$). I'm basically debating between an 8.4" Digital LCD and a Datalux 10.4" Analog LCD. Both are similar in price. I will mount it about 2 feet away from my face in my car.

Also, what nits ratings do you guys think is needed for an in car LCD? I know that some people say up to 1200, but anything above 200 is really damned expensive, and a lot of the real digital LCDs that I see are only like 80 nits. However the Datalux ones are 200nits, which is certainly better, but I don't know what I need. I do know that even a brand new laptop with a screen that is toted to be "readable in direct sunlight" is pretty much useless in direct sunlight, and not very good in company of a lot of light.

Anyways, thanks for all of your help guys!

Fosgate · 11-07-2001, 09:44 PM

To start with all the LCDs are digital. You can have ones with different input though.
Not to complicate things lets say there are 3 main type of LCD you could use in your car. One that connects to your VGA port... They usually expensive but you get CRT like quality. Another type will accept composite input which connects to your TV-Out and usually doesn't have a good quality and generally text is very hard to ready.
And last one is driven by a controller card that plugs in to your PCI or ISA slot, they generally expensive but quality is excelent. Only thing is extending the cable could be a problem.

Telek · 11-08-2001, 09:54 AM

Yes yes, I was aware of the distinctions there, what I was referring to was the *input* type. Anything that plugs into your VGA port (or worse, your TV-out) is analog input. If you have a kickass video card that has a DVI-out then you can usually attach that directly to high quality LCDs to get true digital output (one pixel on the output is one display pixel, whereas with analog it's more interpolated so you get more than one pixel sometimes actually controlling a virtual pixel)

The question was is the analog one that plugs into your VGA port decent enough to be used? Can you read fine text on it?

I can find some decent analog (VGA connector) LCDs but I wanted to know if anyone thinks that these are decent enough, or should I find a real digital-input LCD?

PaulzY · 11-08-2001, 10:08 AM

err your home computer monitor, is analog (well at least most ppl's are), can u read fine on it? yes of course you can

vga signal is good for text
ntsc signal is not good for text

Telek · 11-08-2001, 11:39 AM

Yes, however my home display is a CRT that is specifically designed for use with a VGA analog input. I have no idea how a VGA analog input would show up on a 8.4" 640x480 screen or how text would look which is why I wanted to ask.

MikeHunt79 · 11-08-2001, 03:14 PM

i have an old old tft monitor (like the ones u see in pc world) which takes a vga input.... the quality is exellent, the text is sharper than a normal crt monitor, but it is tft.... it`s a taxan crystalvision 100...
it will be in the car soon, with any luck, as it`s 640x480

kiddigital · 11-12-2001, 02:08 AM

As alrady posted here, all LCD's are digital by nature.

The input type differs though. If you get a pre-assembled LCD unit, it will have a digital LCD unit and a specif hardware driver that converts a certain input type (analog vga/digital DVI/etc) to the digital LCD signal.

When you buy a non-assembled LCD kit, you will probably get something like the LCD unit, a backlight inverter and a piece of hardware to control your display. This piece of hardware is the part that has a certain input type.

Nowadays, there are PCI LCD hardware cards. This means no additional hardware conversion is needed to convert the input signal to the correct LCD signals. Unfortunately, the signals used to drive a LCD panel differ per type/manufacturer. This means you really have to search well to find a LCD panel (not pre-assembled!) with it's corresponding backlight inverter and it's matching PCI based driver card.

Once you find a good matching set of components, then you're of for a good display. There is no need anymore for a graphics card (because you have one with the PCI LCD driver card) and you are able to digitally drive your LCD, so you can avoid 'noise' on your display picked up by most analog VGA cables.

Hope this helps...