Silly errors in design or A vendor gets embarrased

PeteS wrote: ... snip ...

Interesting how simple design stuff gets missed in the rush to get to market.

But seriously, I would be interested in more details. We are on the lookout for this type of display for instruments readable in full sunlight, and none of the CCFL units are good enough.

--
Regards,

Adrian Jansen           adrianjansen at internode dot on dot net
Design Engineer         J & K Micro Systems
Microcomputer solutions for industrial control
Note reply address is invalid, convert address above to machine form.

Well, the CCFL unit we currently use is popular because it is readable in full sunlight (but that's UK sunlight ;)

What output (lumens) do the ones you have looked at advertise?

One thing about white LED; the output is lower than CCFL generally, but they are just as readable because the emitted spectra is white, not somewhat blue.

Once I get back to my real news account (tomorrow night) I'll give details of highly visible CCFL (provided you aren't in direct competition with me ;)

Cheers

PeteS

I was trying to follow your instructions....

Is that

snipped-for-privacy@internode.on.net

?

I consider myself to be quite intelligent but it took me a bit of time to work it out so maybe I am not.

Thanks

DNA

Why six wire, instead of four wire?

--
Service to my country? Been there, Done that, and I\'ve got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

If your country has a government "Adult Protection" group, *WATCH OUT* that you do not get charged with felony abuse; eg: you threw her down the staircase that is not in the house, you beat her. In otherwords, you are guilty without any choice of even knowing the charges until they toss you into jail! This shit happens here in the US (in every State) nevermind it it totally against the Constitution. Nurses, doctors, "aids" that you pay come in to help with her care all have a vested interest to "rat" especially if one of them sees a way to gain (gets an idea you are rich and lets the State take over the assets that they control, political gain, etc); they support each other. It snowballs; 5 "aids" helping at different times sees the same thing, reports the one "problem" and it is a serial offense multiplied by five. I have been pushed against that wall, so BE WARNED!

Most (not all, of course) regulators designed for LED backlights sense on the low side, post cathode. In that case, I need each separate cathode path for sense and each separate anode path for drive as the voltages across the strings will be different (not by much, but they will be).

Cheers

PeteS

Lowest bidder syndrome. Factor in your time and effort in teaching them how to correctly do what they claim to do and it might not be so cheap :-).

Not that more expensive bidders never suffer from the same problem!

Tim.

Genome wrote: ... snip ...

You are intelligent enough.

-- Regards,

Adrian Jansen adrianjansen at internode dot on dot net Design Engineer J & K Micro Systems Microcomputer solutions for industrial control Note reply address is invalid, convert address above to machine form.

I design systems for glider ( sailplane ) instruments, and we need visibility such that the display can be read at a glance, with the sun at any angle. The best units I have seen are used in marine apps, eg fishfinders, but I havent found a source of the LCDs they use yet.

I have looked at units advertised as 600-700 nits, and in full Australian sunlight the colors wash out almost completely. The remaining image in monochrome is readable, but only just, and nowhere near what an ordinary dot matrix mono transflective LCD can do.

--
Regards,

Adrian Jansen           adrianjansen at internode dot on dot net
Design Engineer         J & K Micro Systems
Microcomputer solutions for industrial control
Note reply address is invalid, convert address above to machine form.

I am looking at (and probably going to use) a Kyocera panel. I'll have to wait until tomorrow at work to get the precise part number. This is

5.7", QVGA, but they do other sizes and resolutions.

I was personally impressed with the readability in full on light, but the best way is to get a sample and look at it yourself, of course. Do you have a Kyocera rep. in your black book?

Cheers

PeteS

Thanks for that. I looked at the Kyocera panels, but the max advertised brightness is still only 300 nits, which I know is not enough.

--
Regards,

Adrian Jansen           adrianjansen at internode dot on dot net
Design Engineer         J & K Micro Systems
Microcomputer solutions for industrial control
Note reply address is invalid, convert address above to machine form.

I have a close acquaintance who deals with avionics (cockpit) equipment and the associated panels. I'll drop him a line and ask, but I can't guarantee anything, obviously.

Cheers

PeteS

Here's the response of the guy I used to work with:

****************************************** All the LCD panels I worked on (that were in production) used flourescent backlighting. The backlighting was adjustable with a rotary knob. flourescents were used as they were the best option at the time.

we did some experiments with leds. white leds are now the better solution. they should be bright enough (the leds at least). they are also more reliable and don't require a high voltage supply. i remember the only issue i had was matching the white led dimming curves to the old school flourescent and incandescent.

i seem to remember that there were no COTS solutions for LED backlights that were acceptable for avionics. it is necessary to design your own to get the brightness and uniformity that is required. these guys make the brightest, i think...

i saw an article reciently that a new white led was just as bright and energy efficient as a flourescent.

it is essential to have a anti-glare coatings on the glass and a mechanical glare shield otherwise the glare will make any display useless.

organic LED displays will be an excellent choice as a LCD replacement when the technology stabilizes and manufacturing can maintain the same panel for at least a few years. *************************************************

Cheers

PeteS

Hi Peter,

while talking displays - today I heard on the BBC Worldservice about some $100 laptop project at MIT (easy to lookup). They claim to have achieved so far something like $140; the display they use is an SVGA... I wonder where do they find those apparently sub-$100 SVGA TFTs so I could go there find one myself. I tend to find them at $500+ so far... I found the largest selection of displays - and one which I'll probably use soon - at Toshiba. How much of those are really to be had and how much do they cost I don't know, though.

Dimiter

------------------------------------------------------ Dimiter Popoff Transgalactic Instruments

------------------------------------------------------

PeteS wrote:

Maybe it's because the 'standard' sizes are made in such volumes that they can get that price, but I've yet to find one anywhere close to that.

Cheers

PeteS

Thanks for that, I will follow up.

-- Regards,

Adrian Jansen adrianjansen at internode dot on dot net Design Engineer J & K Micro Systems Microcomputer solutions for industrial control Note reply address is invalid, convert address above to machine form.

Thanks. I had to leave the design field when my health failed over five years ago, and everything in our equipment was CFL tubes.

--
Service to my country? Been there, Done that, and I\'ve got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

The vendor stopped by today with the engineering sample, and sure enough, just two wires sticking out. He gave the usual '..this is how everyone does it...' so I showed him my sample from Kyocera (with 6 power leads - 2 for each LED string) and he was rather flummoxed.

I'll test it, but I don't hold out much hope as it's a dense design and some localised heating is unavoidable.

Cheers

PeteS