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LCD laptop brightness - CCFL vs. LED

Posted on 2011-03-17
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I have a dv9500t laptop with Ultra BrightView display (has 2 CCFL).  It really POPS in the sunlight when I crank up the brightness (and it gives me a massive headache indoors if I forget to crank it back down).

Sadly, that is PAST tense... the machine died under extended warranty and HP is replacing it with a newer model.

However, the newer model they suggested only has a BrightView display (not Ultra BrightView).  The case manager is telling me that LEDs are "brighter" and so this should be just fine; he also emphasized the more vibrant colors from the LED display as if that has something to do with brightness(?).

The dv9500t BrightView had a brightness of 200 nits or 200cd/m2; I assume that with 2 CCFLs in the Ultra BrightView, that means the Ultra BrightView would be about 400cd/m2 (is that the way this works?)

The dv7 BrightView display has a brightness of 200cd/m2.

My question: is my ability to see in sunlight (i.e. high ambient light environments) solely / primarily a function of the brightness of the display?  Will the dv7 LED BrightView at 200cd/m2 be able to come close to the dv9500t Dual CCFL Ultra BrightView display where just ONE of the CCFL puts out 200cd/m2?

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Question by:SAbboushi
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by:garycase
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Dual CCFL's doesn't mean double the brightness.

In fact, the dual lamp display on a dv9500t has a rated brightness of 200 nits  (the single lamp is rated at 180 nits)

So I'd expect the LED illuminated display to be just as bright as what you're used to.

Note that BOTH of the display panels are LCD panels -- the CCFL/LED designation simply refers to the source of the light that illuminates the display.    LEDs are also far more reliable than CCFL tubes ... so at least from the display panel perspective you're getting a nice upgrade.
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by:nobus
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by:SAbboushi
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garycase: thanks for your feedback; I would value any sources you can cite that support your position (e.g. the ratings of the lamps).

>> Dual CCFL's doesn't mean double the brightness.
If both CCFLs are identical (i.e. same length, same part#), then why would it NOT mean double the brightness?

nobus:
Thanks - good article, but I don't find that it answers my question.  Conclusion that I gather from the article: Brightness of an LED LCD panel is a factor of the number of LEDs in the panel.

It seems to me the only true measure of brightness is cd/m2 (nits).  The latest service manual for the dv9500t says "TYPICAL" brightness for single CCFL is 200 nits; and that "TYPICAL" brightness for dual CCFL is 200 nits.  I agree that this is the TYPICAL level (i.e. I RARELY crank up the brightness on my dual CCFL display), but it makes no sense to me that this is the MAXIMUM the panel can put out (i.e. it makes no sense to me that the Ultra BrightView with 2 CCFL is the same brightness as the 1 CCFL BrightView - otherwise, WHY exactly did I pay a couple hundred dollars more?)

I ran my display at LOWEST brightness in my office and HIGHEST brightness outside.  I can look at that display in my office for 80 hours a week and be fine; but if I come from outside and forget to reduce the brightness, I get a searing headache within minutes in my office -- the dual CCFL is that bright.  Looking at the LED LCD panel on the dv7 indoors at maximum brightness, NO SEARING HEADACHE.  No way it is anywhere NEAR as bright as the dual CCFL Ultra BrightView that I have.


I would appreciate any comments that help identify any mistakes in my reasoning / knowledge on this.
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by:garycase
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The stats are from HP's Service Manual for the dv9500t:
http://h10032.www1.hp.com/ctg/Manual/c01951704.pdf

Note that a dual CCFL panel almost certainly is not designed to drive the CCFLs at the same level as it would for a single CCFL panel (as the specs would tend to show).
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by:SAbboushi
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nobus - thanks for the link - again, it seems that nits or cd/m2 is the relevant metric here.

garycase:
>> Note that a dual CCFL panel almost certainly is not designed to drive the CCFLs at the same level as it would for a single CCFL panel (as the specs would tend to show).

Why would you say that?  What specs are you referring to that show this?

the link you posted - that's the same version I was referring to (service manual).  It shows the SAME brightness (200 nits) for both the single and dual CCFL which is labeled "typical".  That CANNOT be a maximum number - the difference in brightness between the single vs. dual CCFL is HUGE - that is why I decided to upgrade to my first Ultra BrightView laptop display years ago after comparing the single CCFL vs. dual on the dv800t at Best Buy.  It looked like it was about double the brightness, but I wasn't aware of "nits" metrics back then.

I just found this link:

http://www.notebookreview.com/default.asp?newsID=2881

"HP advertises Ultra BrightView as achieving nearly plasma TV levels of brightness, and the difference in brightness between two and one lamp is significant."

There is also a photo of 2 screens side by side where you can see the brightness.  

Again, looking for critique on my analysis

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Agree the "Ultra Brightview" allows you to turn up the brightness more than normal -- and obviously it's brighter than a single CCFL when you do that.     On the other hand, the LEDs can also be "cranked up" to brighter-than-normal brightness.    Unfortunately, HP does not provide maximum brightness specifications for either, so it's hard to say just how much difference there really is at max brightness for either.

The service manual has somewhat different specs on different pages.   On page 4 it notes "typical" levels of 200 nits for BOTH the single and dual lamp displays.    But on page 111 it shows a typicall 180 nits for the single lamp display.

I suspect the answer is that indeed the dual lamp CCFL CAN be brighter ... but I suspect the LED lit display is plenty bright for MOST uses.    

Note, by the way, that the comparison in the review you noted above is between the HP dv9500t and the Toshiba M35.    I'd think was a far more accurate comparison if it was betwen the two versions of the HP.


In any event, this is probably academic, as I don't believe they offer an UltraBright version of their laptops anymore -- so if you want to take advantage of the upgrade to a newer system you basically don't have a choice.    I'd go to a local store and "crank up" the brightness on one of the LED-based HP Laptops and see what you think.     If this is a major issue for you, then refuse the new system and insist they repair yours :-)
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by:SAbboushi
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thanks garycase - your input has been most appreciated.
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by:Qlemo
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This question has been classified as abandoned and is being closed as part of the Cleanup Program. See my comment at the end of the question for more details.
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