Brightness of 300 vs 350 nits - Practical difference?

jasonsjwou · 10-02-2006, 04:04 PM

First of all, what is the unit of brightness mean (NITS)
Is this same as cd/m2 ?

There are three screens (10.4inch) that I am considering.

Lilliput (350 nits, 180:1 Contrast)
Ebay "Munchikin" (300 cd/m2 , 400:1 Contrast)
Litton mobileVU (1300 nits)

I am quickly disregarding the litton mobileVU LCD.. it has like 8 bit color, and consumes like 60watts. It's bright alright, but may be too much.

Contrast ratio is also important in terms of picture quality.. It's a trade off. Usually really bright screens cannot achieve deep blacks.

So,

What would be the practical difference between 350 and 300 nits? Would it be okay to lose 50 nits and gain 200:1 contrast ratio? Or does the last 1 nits count?

My 06 Accord has a black cloth interior, tinted window (35%) and I'll be mounting this in the middle of the dashboard where the stock CD changer is.

JuMpMaN6235 · 10-02-2006, 04:29 PM

can you put a link to the Munchikin one... Oh and cd/m^2 is the same thing as Nit, its a measure of luminance

jasonsjwou · 10-02-2006, 10:03 PM

Here

http://www.mp3car.com/vbulletin/show...highlight=10.4

and here

http://cgi.ebay.com/10-4-TFT-LCD-Tou...QQcmdZViewItem

turbocad6 · 10-02-2006, 10:07 PM

reported nit brightness ratings is a lot like amplifier power ratings, alot can be left to interpitation & differing testing methods...

nit brightness is really measured at many different points on the lcd... some will report the highest readings as the nit brightness, other companies will report the average across the screen as the nit brightness, & the best screens will report the lowest readings as the nit brightness, meaning it is always at least as good as there spec at any given point...

I think I'd choose the much higher contrast ratio over the slightly better nit rating, but in the end, it's the reflections that will kill your display in the sun more than anything else, this is where a good anti-reflective touchscreen comes into play, or eliminating the touchscreen all togeather maybe...

turbocad6 · 10-02-2006, 10:10 PM

off course, the variable in the above ratings are assuming there both talking about the same thing, either both before the touchscreen or both with the touchscreen attached, otherwise your comparing apples to oranges...

jasonsjwou · 10-02-2006, 11:24 PM

I see.

So the touchscreen layer reduces overall net brightness... then how much am I losing? If the LCD panel is 300nits without touchscreen, then will I get 250 nits with touchscreen? 200 nits? or does that depend on various things?

Do you know if anyone sells 10.4" LCD that is 500+nits, 400:1+ Contrast ratio, with the touchscreen?

turbocad6 · 10-02-2006, 11:56 PM

it depends,, some resistive touchscreens may be like 85% transmissive, others can be over 90%, some capaciative screens are like 96% transmissive, but capaciative screens are usually more glare from the shinnier surface that's typical of capaciative screens..

there are many good screens when you talk about 10.4" sizes... all the way up to real high end & real expensive... you should be able to find many great screens if you want to spend what it'll take...

JuMpMaN6235 · 10-03-2006, 12:00 AM

you can always upgrade the CCFL's

turbocad6 · 10-03-2006, 12:01 AM

btw, most really cheap resistive touchscreens, like those used in lilli's & stuff, can be in the mid 70%'s range of transmissive, means a 350 nit screen will only have an effective end result of less than 220nits, combined with the glare it's no wonder you can't see it in the daytime

jasonsjwou · 10-03-2006, 12:10 AM

What kind of brighness would a Factory OEM touchscreens have?

turbocad6 · 10-03-2006, 08:45 AM

there are more factors than just brightness... a sunlight viewable screen with a not so hot touchscreen may need to be 800-900 nits, to get the same results of a 450-500 nit screen with less reflective touchscreen properties...

most factory screens aren't super bright high nit, but they have 2 big advantages in most cases, 1 is that the dash is usually designed with the screen on an angle & recessed, & the 2nd is there is usually more $$ in r&d for optically matched components, some use bonding technology too... & then some eliminate the touchscreen all togeather in favor of better viewability like bmw, etc..

bonding is great because with a typical touchscreen there are really 3 main surfaces to reflect, the front of the lcd, the rear of the touchpanel, & the front of the touch panel.... when there bonded togeather the touchscreen is bonded to the lcd, & the result is there is now only 1 surface to reflect, the outer touchscreen only.. this, combined with antireflective coating, gives great results without excessive nit brightness....

Motorcity · 10-04-2006, 12:16 AM

Quote: Originally Posted by turbocad6

btw, most really cheap resistive touchscreens, like those used in lilli's & stuff, can be in the mid 70%'s range of transmissive, means a 350 nit screen will only have an effective end result of less than 220nits, combined with the glare it's no wonder you can't see it in the daytime

75% of 350 nits is 262.5 nits.

like you said, touch panels do block some of the light, but most are usually in the 80% neighborhood.

I would take the higher contrast ratio over the higher brightness.
But, ( and this is a big but) you really can't rely on the advertised numbers on the monitors you see on ebay.
I have bought so many of them from differnet vendors, model #'s, etc.
The crap they advertise is unreal.
Here is what I have learned: 800x600 is really 640x480 resolution.
1280x1024 is really 800x600
400 nits is really 190 nits
(this is based on manufacturer's specifications for the actual lcd panel in the monitor)
"new panel using Sharp technology" is really 12 year old Hitachi, NEC, or Hoisden panel pulled from pachino machine.
Bottom line is you really won't know what you are geting until you open up the monitor and check out what panel is in there.
They can publish all the specs they want, advertise resolution scaling, etc. But the actual native resolution of the lcd panel, and the backlights in there, along with the lcd manufacturer's listed contrast ratio is what you will ultimately end up with.
It is my opinion (based on proven fact) that the Lilliput monitors (8" and larger) have advertised numbers that are accurate, for the most part.

turbocad6 · 10-04-2006, 12:45 AM

awe man, I didn't want to have to break out the calculator

your right, specs don't mean anything on those packaged ebay screens, the real specs are from the data sheet of the actual lcd, which can be nothing like the "claimed" specs...

jimbo4 · 11-24-2006, 11:54 AM

I've looked around but haven't found anything related to this so I figured I would ask... Playing around with a "beta" version of a carputer... trying to run a Litton MobileVu 46850 touchscreen off of an older Compaq laptop. Was able to finally find drivers for the touchscreen but am having problems with the resolution. I can either go with 640x480 or 800x600 on the laptop - but the doesn't fly so good on the touchscreen... cannot calibrate properly, etc. I think I need 800x400 or so (?) I'm totally fried here, having google'd my butt off for the lst several nites. Any help is deeply appreciated!! THANX!!

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