QXGA LCD Panels now cheap ... good enough for variable resolutions?

[olePigeon]

So the QXGA panels are now cheap on eBay.  Especially old 15" Lenovo laptop LCDs.

For around $100 I could get a 15" 2048x1536 panel + a combo LVDS controller/inverter board.  What I'm wondering is if the pixel density will be good enough at 15" to not notice scaling effects on resolutions that aren't 640x480 ratio.  800x600, 1152x864, 1280x1024, and 1600x1200 for example.

What do you guys think?

 

[olePigeon]

Also, I'm having issues finding a driver board that supports QXGA and also has a VGA connector.  I'd like to avoid using a VGA to HDMI adapter. :/

 

[Cory5412]

I kind of suspect you'd still notice.

Most 4:3 and 5:4 17-20-inch business LCDs from ~2003-today do fine at 640x480 through 1280x1024 or 1600x1200 depending on particular model, even oddball resolutions and sync rates such as Sun's 1152x900.

In my experience, they look fine when scaling. You of course know that it's scaled, and not all displays do a good job of, for example, keeping pixel ratios exact. Some high end displays will do a centered 1:1 mode.

Another option if you know you have a specific target resolution, either buy a display at that resolution or pick a different resolution. For example, you could get a video card to just support 1280x1024 output on a Quadra if you didn't think 1152x870 would look good on an LCD, or do a VRAM upgrade on a PCI PowerMac to get to 1280x1024, or VRAM-upgrade or put a Rage128 in a Beige to get good 1600x1200 with 24-bit color. (The other option in most of those scenarios is to go down to 1024x768, which 15-inch LCDs will do fine.)

It might be worth trying, but 19-inch 5:4 business LCDs are $20 a pop and are available in quantity all over the place.

 

[olePigeon]

@Cory5412  Do you know of which models have a 1:1 centered mode?  I've seen it before, but I've never owned an LCD that can do that.  That would be my preferred solution.  Maybe a 19" monitor that doesn't scale.  I also don't know what terminology to search for that feature.

 

[olePigeon]

Did some Googling.  "Fixed Matrix Display" is what I want.  Looks like HP uses it on some of their monitors.  I'll look around.

Oops, nevermind.  HP explaining how LCDs are Fixed Matrix Displays, and how they don't use that feature because it doesn't utilize the whole screen.  Bah.

 

[Trash80toHP_Mini]

Also, I'm having issues finding a driver board that supports QXGA and also has a VGA connector.  I'd like to avoid using a VGA to HDMI adapter. :/

I doubt there is such a thing as the controller you seek. VGA to HDMI is probably what you'd need to do. I'm not so sure even that would work as you'll likely need a clean QXGA signal to be downscaled? 1920x1200 (WUXGA) is a hard ceiling for Analog VGA from what @trag and @Gorgonops have said. QXGA is likely to be a pixel too far for anything 68K or NuBus/030PDS architecture. Dunno if there's support for QXGA in PCI or if it'll require a card from the AGP era?

 

[jessenator]

My Sony SDM-X82 monitor supports 1:1. Not sure of the LCD p/n without dismantling it. However its native max resolution (that I've tested so far) is 1280x1024.

 

[olePigeon]

@Trash80toHP_Mini  I'd never run it at QXGA.  Maximum 1600x1200.  However, I'd be happy running it at 1:2 natively at 1024x768, so long as it looked fine at 800x600 and 640x480.

 

[olePigeon]

Ideally I'd like an LCD monitor that could do this:  19" 1280x1024 native resolution.  1:1 mapping at 1024x768 and 800x600.  2:1 mapping for 640x480.

Anyone think a monitor like that exists?

 

[Trash80toHP_Mini]

Belay that bit about needing to do full res for downscaling. Makes no sense on second thought. You're still stuck using a VGA-HDMI adapter, but the controller may be expecting a digital only feed if it doesn't have the analog VGA input on board?

 

[olePigeon]

Yeah, I think the QXGA display idea won't work.  I'd have to use a VGA to HDMI scaler just to connect to it.  It'd suck.

 

[Cory5412]

It sounds like the intent is to do scaling on a really high pixel density laptop screen, with the idea that if the display itself is high enough resolution, it will look better to upscale, say, 640x480 to it.

The 2048x1536 panels being cited are laptop screens from ThinkPad R51 and T42/T43 laptops, which also means they're close to fifteen years old and unless you refresh the backlighting on them will end up looking a bit weird by modern standards anyway. (Though, a desktop LCD from 2003 will also have that problem, it's just that those are, you know, $15 from your local goodwill.)

1:1 modes tend to appear on fairly high end displays, Eizo, maybe certain NEC models. I'm not entirely surprised to hear about a Sony with it.

I'm guessing that there aren't any displays (or many, at least) with 2:1 modes, though if you went and found, like, a 1600x1200 display, you could run that at 800x600 and it would probably look okay.

One option I've seen before is scan converters, but most of those are optimized for getting output from something like a IIgs or a video game system onto a VGA display. I don't know what options there might be to get 640x480 onto a more modern consumer-oriented display that doesn't have VGA input. (Which: you have to look hard to find a monitor without VGA. This one for $130 from the local Target even has VGA.)

 

[Trash80toHP_Mini]

I doubt there is such a thing as the controller you seek. VGA to HDMI is probably what you'd need to do.

Belay that, I meant DVI in all the posts above - morning fuzziness.  :

Yeah, I think the QXGA display idea won't work.  I'd have to use a VGA to HDMI scaler just to connect to it.  It'd suck.

Had a thought at work, since the screens are LVDS, they may run at lower resolutions from a VGA equipped PiVerse LCD controller board? Maybe it's what signal that hits the panel over digital LVDS that counts. It might wind up being letterboxed 1600x1200 to be useful. It all depends on what it depends. This LCD Controller looks interesting:

,

Didn't see specs on max resolutions supported on this or any other controller in the time I had. My guess is that if it's cheap it's probably for and maxed at 1080p. I'm guessing you won't find that connector on a laptop panel, it'll be flexcable interface, which  poses something of a problem.

 

[lameboyadvance]

So the QXGA panels are now cheap on eBay.  Especially old 15" Lenovo laptop LCDs.

For around $100 I could get a 15" 2048x1536 panel + a combo LVDS controller/inverter board.

...Are you sure those are actually LVDS controller boards? I've been holding on to a boxed IAQX10 for over a decade in the hopes of turning it into a monitor. To date the only controller I've ever heard of for it was custom made by some guy in china who just disappeared off the face of the map one day.

The only QXGA controller boards I see for sale nowadays are eDP and made for those 9.7" iPad LCDs.

 

[olePigeon]

@Trash80toHP_Mini I was looking at that one, too.  The letterbox doesn't bother me, it's exactly what I want, actually.  No scaling.  Then again, it'd all depend on that controller board.

 

[olePigeon]

@lameboyadvance  According to the data sheet it's 6-bit LVDS.

https://www.datasheet4u.com/datasheet-parts/IAQX10M-datasheet.php?id=842172

 

[lameboyadvance]

@olePigeon I know its a LVDS panel, what I'm saying is I've never personally seen a LVDS controller board capable of achieving a high enough resolution to fill it. All boards I've seen top out at 1920x1200.

Are you saying you've actually found a controller that goes all the way to 2048x1536? If so I'd love a link to it.

 

[olePigeon]

@lameboyadvance  The one used in the ThinkPad that utilized this monitor.  I don't know of a cheapy universal controller board that supports it.  I think I've seen some custom programmable ones.  Would be worth emailing and see if they can get set up to drive QXGA.

 

[lameboyadvance]

Oh, so you are saying you're just driving the LCD from an actual Thinkpad board? If thats an option I may consider it, but I don't really want a fullblown computer running as the monitor 'controller'.