Hi all. I've been searching, but cannot find a reasonably priced graphics display module around 320x240 pixel; pref touch screen. Must be low current/voltage backlight. parallel or serial drive no problem. Low price main concern. Ballpark around $US40 in 100 qty.
I got 3 units from Truly which are nice but the backlight consumes 100w! yes thats right 1a @ 100v - same as a TV or computer.
Manufacturers and models recommended appreciate. Cheers, Alistair.
I'm sorry for being sceptical, but are you *sure* you have these numbers right ? If the display dissipates 100 W, it will get *hot*, really too hot to touch. Did you get these numbers from the documentation or did you measure them yourself ?
problem.
I question this too. A CCFL backlight driver for a QVGA style panel should tak about 0.5-1.0 A at 12 V. But you don't say how big the panel is. I regularly use 5.6" mono panels boxes that would melt at 100W and the power supply for the whole unit is 35 W (but we never draw that much).
Peter
Fair comment - I have not actually applied the voltage to try it and see.
The model is Truly MFT-G320240DPEW-4N and EL backlight enable volts are
100-150vac. Now, if enable just means a pulse and it drops back to say 25v then Ok, but the specs dont say this. Here is what Truly say about backlight current: Dear AGEORGE, MG320240-4 EL BACKLIGHT CURRENT:900MA(TYPE) (IN CONDITION: 100V 400HZ AC) Its a 320 x 240 pixel LCD module as previously described. Maybe someone with more experience in these EL backlights can educate me? Alistair.
The backlight is usually driven by a special DC-to-high-voltage-AC converter; it just converts the DC voltage to a few hundred volts AC, and loses a few percent of the energy by heat dissipation.
I assume the specified current is on the primary side, probably at 12 volts. 12 V * 900 mA is about 10 Wattsi, which sounds ok to me.
The 100-150 volts AC is the voltage at the output of the converter, which is connected to the lamps in the display. The current on this side probably no more then approx 100mA.
e=2E
I have a product with a 5.7" QVGA unit. You are correct, they aren't cheap, at least in TFT style. STN panels are cheaper, but aren't as sharp.
Generally, it's cheaper to buy one complete with the display control circuitry (unless you intend to make a few hundred thousand). My panel complete with controller sets me back around =A375 or so in 10k qtys. (Including the backlight of course).
For the backlight, I use a 5V (input) CCFL controller andf it draws just about 1A @ 5V for full boosted brightness, about 900mA for full unboosted. The output runs at about 700Vrms, around 80kHz and about 5mA rms. The backlight inverter (as a separate board) costs about =A316. If you do your own, you can shave about 50% off that.
Touchpanel - I use a polycarbonate touchpanel as the device is designed for rugged use. Metallised glass is cheaper, but breaks more easily.
Hope that helps
Cheers
PeteS
OK thanks again for info. To claim .9a at the source, not at the load where the voltage specification applies is not the way I would have given the spec. So now the .9a makes sense. Cheers, Alistair.
problem.
Hello,
I use a 3.8 inch and a 5.7 inch from URT
They are very fairly priced. As far as i remeber I pay about 33USD for the
3.8 inch (Epson controller included onboard) and about 41USD for the 5.7 inch (External controller is needed)Our MOQ is 200 panels.
Best regards Henrik
Sounds excellent. Do you have their email address as I tried to contact them via their web mail and it failed. Thanks, Alistair.
Yes, I will be back in office tomorrow, friday, and I will post the contactinfo here.
Best regards Henrik
Hi,
We have used LCD modules from bolymin. We've gotten quite good pricing from them, although we have not used their colour modules, so I cannot give you a ballpark price. Details at
Regards Anton Erasmus
Have something to add? Share your thoughts — no account required.
Ask the community — no account required