Thread: LCD Backlight Upgrade

  1. #1141
    MySQL Error jcdillin's Avatar
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    yeah but what diameter are those ccfl tubes? because I already tried it with 2 U shaped and it was the same brightness as the stock backlight.
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  2. #1142
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    Quote Originally Posted by jcdillin
    yeah but what diameter are those ccfl tubes? because I already tried it with 2 U shaped and it was the same brightness as the stock backlight.


    roughly 3mm. I'm sure you've exhausted teh possibilities, just throwing out ideas.

  3. #1143
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    doesnt hurt to have different views on the subject, but yeah 3mm are too big, minimum size has to be 2.6mm or the light output is not enough to do any good.

    But our next design is going to be U shaped CCFL's just a few more than 2, we are trying for 6
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  4. #1144
    Super Moderator. If my typing sucks it's probably because I'm driving.... turbocad6's Avatar
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    yeah blue, still working on this & yeah, life still gets in the way I guess.... the box is all complete & painted & the led's are mounted as off last night, haven't had that extra hour or so to solder these up & I have to put a meter on it first to make sure none of the terminal pads are shorted to any of the mounting screws I see two that are really close...

    I keep thinking it'll be done any day now....week after week I keep thinking it'll be done any day now... this thing is winding up having well over 25 hours in it..... & i'm guessing another 5-6 hours in install plumbing & mounting pump, cooler & fan.... reservoir.... that's just the labor & very conservatively estimated.... gotta be quite a few more hours in the research..........

    those stupid expensive helicopter screens are starting to not look too bad.....


    the next picture will be the completed fully lit screen

  5. #1145
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    Quote Originally Posted by jcdillin
    doesnt hurt to have different views on the subject, but yeah 3mm are too big, minimum size has to be 2.6mm or the light output is not enough to do any good.

    But our next design is going to be U shaped CCFL's just a few more than 2, we are trying for 6
    they might be that small.

    multiple U-shaped CCFLs are the way to go, in my opinion.

    I'm pretty sure you could take 2 dual output inverters, take the transformer off one and solder it in parallel with the other, and get 4 outputs. I'm pretty condifent the driving oscilator could handle it.

  6. #1146
    MySQL Error jcdillin's Avatar
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    yup

    erm, possible, but I doubt it. Even if it did work, as soon as you hit it with the inhibit signal to dim them I bet it would freak out


    but it's a mute point anyways, with the new design inverters are much much easier to come by and they even have the onboard PWM that I wanted. We only had a problem with the first tubes that I have sitting in my closet
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  7. #1147
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    Quote Originally Posted by jcdillin
    yup

    erm, possible, but I doubt it. Even if it did work, as soon as you hit it with the inhibit signal to dim them I bet it would freak out


    but it's a mute point anyways, with the new design inverters are much much easier to come by and they even have the onboard PWM that I wanted. We only had a problem with the first tubes that I have sitting in my closet

    you're probably right, and it's not one of those long-term, sell it in MP3car solutions.

    I'd think a company should be able to modify a circuit to handle 2 transformers in parallel. perhpas it is not cost effective for them

  8. #1148
    MySQL Error jcdillin's Avatar
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    I'm sure they could, but it's going to be much easier to use something preexsisting, heck ERG was willing to make us a inverter for the first set of tubes, I just wasnt willing to wait 5 weeks and shell out $400 for a custom inverter design.
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  9. #1149
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    do you have any pics of how the CCFL assembly looks in one of our LCDs? the furthest I've had one apart is to the controller/LCD, not he LCD/cclf

  10. #1150
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    another thing I noticed with lcd's is that I think the tubes are much more efficient if there edge mounted with a factory designed light guide...I don't mean electrically of course but in actual even light transfer

    lcd manufactures spend alot on light guide design.....it's a huge factor in the end product.. I think this is a major factor in adding backlighting by just adding tubes behind the lcd....if you took an average lcd & removed the original ccfl & mounted it behind instead & then got that light to be EVEN the screen will be much, much dimmer.....

    an lcd manufacturer can take two ccfl's & computer design & develope an edge design with light guide & produce a 500 nit screen for example, but you will never be able to have these two same tubes & put them behind the lcd & have your own 500 nit screen, you'd be lucky to hit 150 nit's if your going to take the steps necissary to get even dispersion.....

    this is exactly the reason why multi tubes are the way to go, #1 to get more natural coverage requiring less diffusion & #2 because of the huge loss in efficient light transfer again, because of the losses in the inefficency of the design & the required add'l diffusion

    in order to create your own 600 nit screen, you will basically have to use as much actual lighting as an lcd manufacturer would need to create a 1500 nit screen or more....

    these numbers aren't necissarly acurate, but more my interpitation as used to explain my observations.....

    from all of my calculations & guesswork, my screen will wind up being like 700 nits or so..... if an lcd manufacturer had to build it they would probably have been able to get this twice as bright with 32 1 watt luxeons

    you have to realize this loss in your design....

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