Thread: NEC 8.4" Transflective Solution - Custom Kit

I reviewed the NEC 84PW041 inverter specs in more detail and it offers a fixed pot to control brightness or variable voltage interface (0 - 2.5V) for brightness control. The LVDS-07 interface card on the EPIA can't control the inverter, it can only route the 5V to power it. Thus I would be stuck with setting the pot to max and hope the ST-NLT tech works its magic. Nighttime viewing may be to bright...

A better, and more masochistic , approach would be to spin a small photo-detector circuit. Brief searches yielded the following:

TSL254R: LIGHT-TO-VOLTAGE OPTICAL SENSOR
http://www.taosinc.com/images/produc...SL254R-e12.PDF

I should be able to connect this directly to the inverter, as the VOUT voltage is proportional to light intensity. Response times appear to be fast enough.

The sensor sensitivity would determine if we need only one or an array to determine if the brightness really needs modification (i.e. sun hitting top corner only). The transflective properties of the ST-NLT panel will control the brightness adjustment automatically, so perhaps only the day/night detection is required. I need to see it in action first...

For the near term, I really need to get the cable length measurements to Duayn so he can get started. I will get the LVDS-07 EPIA card and 84PW041 inverter by Tuesday, but won't be able to view the panel...

BTW, Duayn stated the IRTOUCH units make for a clean bezel, so I may be able to Dremel out the double-din area a bit for the 8.4" dimension, sand, and then paint, with no fiberglass work. That would be SWEET!

Originally Posted by thermoptic

I briefly researched CCFL lighting. The NEC has two CCFL, but I was wondering if I could upgrade the bulb strength? Are all CCFL bulbs the same in terms of brightness? I imagine you could have higher quality phosphor coatings, and such.

I don't know how much they can or can't do with phosphors, etc. Something to look into more. I've never really bothered much, because I figured I'd just use longer tubes / more tubes.

If you look at Cd per meter (Mouser's catalog for example), the tubes' output are pretty similar with regards to diameter. (Cd / m^2 does vary with diameter, because a fatter tube has more surface area. Better to look at output per unit length.)

Originally Posted by thermoptic

Maybe drive them a little hotter. The inverter driver may step-in once the voltage or current thresholds have been exceeded. spmclaugh, you mentioned rolling your own inverter. What needs are you addressing (i.e. better efficiency)? Can you comment on CCFL bulb quality?

You could probably drive them a little harder, if you're willing to replace them more often (electrodes will wear out). As far as building an inverter, I wouldn't really recommend it unless you have a reason. The team from our project talked about it more, and we might even go with ERG. The original reason was to get maximum efficiency, customizability, and simply because we were already "on a roll" building other things custom. But for the price ERG charges, it's probably worth the time saved.

I'm in the process of buying the 6.5inch XGA NEC display for a totally different purpose than what you guys are doing, but it boils down to needing an outdoor readable display so here I am.

(Long time lurker, never posted before, this forum has great tech info by the way and I have used the info here numerous times)

I contacted NEC directly and was sent to a distributor. The rep has been very helpful and also mentioned that they (them or NEC, not entirely sure) have bonded 90% transmissive A/R coated capacitive touchscreens to the 6.5" display and that the price was nominal (150$ for the bonding+ touch screen cost) I will post more once I learn more to give back to you guys but this screen seems to be an awesome package for 375$ roughly w/ XGA resolution.

I also read the warnings of UV exposure and will try to find out more from the rep about possible damage. I find it odd that a display marketed for outdoor use would not have a safeguard against normal UV exposure. It defeats the purpose to have an A/R surface if I have to lay down another film on top of it.

byron1, welcome to the thread and thanks for posting. The more information we share the, stronger we all become...

Who was the distributor? Does the $375 cover everything? Based on my very limited research, bonding would cost $300 with a variable $100 to $150 "prototype" tooling fee which covered bond material matching, and such. Do they offer this with 8.4", or did you just get really lucky with your target dimensions??

For UV protection you want soda lime glass. See my touchscreen thread in the Input Devices sub-forum. Don't know if the capactives use this type of glass. See Wikipedia for details.

I think the optimal solution is 3-6 mm soda lime glass optically bonded with multi-layer AR coatings (five is best). You then attach an IR touchscreen on top. Serious coin!

I received the inverter today. Not the most exciting piece of hardware, but still very crucial. Note the high voltage warnings. Do not touch!

I'll post connection details tomorrow. Too tired now....

Originally Posted by bryon01

I contacted NEC directly and was sent to a distributor. The rep has been very helpful

Hi, good luck on your project. Question: mind telling who the distributor was? I'm trying to call every NEC distributor I can find, hoping someone will have the LED backlit version of the 6.5" transflective.

As far as the UV exposure, I'm personally just "hoping for the best". Not usually a good strategy, but in a car, I just don't see these displays wearing out too quickly from the sun. Maybe for your project though.

Hmm, seems you guys have a pretty informative thread going here. I'll toss my $.02 in:

I've been looking for 10.4" panels, so my requirements are a little different. But, I stumbled on these guys: http://www.litemax.com.tw/index.html

Anyone have any experience with their panels? I've been looking at this one, getting pretty tempted: http://www.panel-brite.com/Graphics/LF1055E.pdf

Wide viewing angle isn't much concern for me, due to where I'm mounting it in the vehicle, but its not too shabby. Anyone know of a model that can beat it?

I received the LVDS07G today. The VIA CN700 North Bridge drives the NEC panel via the Via VT1631L LVDS transmitter chip on the interface card. Inverter connector can supply either 5V or 12V and the panel connector can supply either 3.3V or 5V. This is a dual-channel LVDS driver card but the NEC is single channel.