different result for same panel in 3 different models?

Discussion in 'Dell Latitude, Vostro, and Precision' started by bycicl, Oct 3, 2015.

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  1. bycicl

    bycicl Notebook Geek

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    hi,
    is it possible that 3 different models with the same panel would have different measurments (brightness, contrast, color, black)?

    dell e5540, e6540 and 3540 are using the same panel according to notebookcheck.com reviews, but the results of the measurements are very different.
    thanks
     
  2. John Ratsey

    John Ratsey Moderately inquisitive Super Moderator

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    I think the brightness range can definitely be programmed into the BIOS as a range for the backlight voltage and I also believe that the other parameters can be put in the BIOS as default settings for the display which then get passed to the operating system. However, I am less certain, when a notebook manufacturer uses several different displays for a notebook model, whether they program in different settings for each panel or just use a generic set of values.

    I suspect that most manufacturers are lazy when it comes to setting up the display although that doesn't explain why Dell would use different values for different notebooks. My Spyder 4 Express calibrator has paid for itself because it's rare to find a notebook where the display settings can't be improved on. The calibration settings will override the defaults for everything except the brightness range.

    John
     
  3. bycicl

    bycicl Notebook Geek

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    Hear hear. I’ll change my question a bit.

    is it possible that notebookcheck doesn't give the accurate model of the panel? I re-checked the reviews in notebookcheck. All three reviews feature the same panel: AU Optronics B156HW02. But they don’t specify the version of the panel (V.1, V.2..) In all three reviews the contrast, color, black and brightness results are pretty different (results are shown pre and after the calibration). for example the dell e5540 is notorious for it's bluish cast (by notebookcheck). that quality doesn't really appear in the reviews of the e6540 and 3540.

    so, when planning to upgrade the screen and opt for extra brightness, one must only look for a similar or a matching backlight voltage? how to tell?


    http://www.notebookcheck.net/Review-Dell-Latitude-E5540-Notebook.115887.0.html
    http://www.notebookcheck.net/Review-Dell-Latitude-E6540-i7-4800MQ-HD-8790M-Notebook.97595.0.html
    http://www.notebookcheck.net/Review-Dell-Latitude-3540-Notebook.105885.0.html
     
  4. StormJumper

    StormJumper Notebook Virtuoso

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    Here is a better point just contact Dell Support and ask them-is it that hard to do??
     
  5. bycicl

    bycicl Notebook Geek

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    they dont have this exact knowledge of course. its a pure technical matter. my question is what qualities of the screen are pre-set in the laptop itself and what qualities are determined by the screen.

    (moreover, how to make sure that you'll be able to buy a replacement screen and enjoy from its maximum brightness or other features).
     
  6. John Ratsey

    John Ratsey Moderately inquisitive Super Moderator

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    I think you will find that you are stuck with whatever brightness range is programmed into the BIOS. I'm 99% sure that somewhere in the past I did a BIOS update that changed the display brightness. Have you searched for the detailed technical specs for the notebooks in question to confirm the design brightness levels?

    There can be several reasons for notebook manufacturers not giving customers the maximum brightness supported by a panel. One is that a different but compatible display (Dell always uses at least two sources for displays) can't handle the maximum brightness of your preferred option. Another is that the maximum brightness was intentionally reduced in order to extend the battery run time. It is also probable that there is some variation in individual performance of displays with exactly the same part number. It is also possible that configurations within the graphics driver (such as auto brightness and Intel display saving technology) have made the brightness lower than the maximum and weren't detected by the reviewer.

    As for alternative compatible panels, the key features to check for are the number of contacts on the cable connector and the location of the socket. The specialist replacement display sellers usually list the compatible alternatives.

    John
     
  7. bycicl

    bycicl Notebook Geek

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    Thanks John,

    Unfortunately I did encountered this same problem of “same panel and different results in a few other notebookcheck reviews”. The differences were significant.

    I’m about to receive Dell latitude e5540 that is really to my like. According to dell, the FHD TN latitude E5540 model comes with up to 300 nits of brightness, so according to you I’m not supposed to be concerned, but this model only comes with a TN panel. What parameters do I need to insure before purchasing IPS screen that will match?

    Laptopscreens.com and one other screen reseller can only recommend for one type of IPS matte panel that will work (LP156WF4-SLB2) but that screen has bad contrast, color reproduction etc. I’m attaching the info page of this panel. Can you take a look and say if there is something unique about this panel (or if it is possible to find a similar and better alternative screen)?

    http://www.panelook.com/LP156WF4-SLB2_LG Display_15.6_LCM_overview_16605.html
     
  8. John Ratsey

    John Ratsey Moderately inquisitive Super Moderator

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    See here and here. There may be more discussion if you read on but if you identify which other Dell models have the B156HW02 as one display option but also offer a high viewing angle panel then you track down what panels those are. This approach isn't infalliable because Dell might use a different display cable for different panels.

    Something else I would highlight is that IPS is a technology specific to LG-Philips. Other display manufacturers use other technologies to give high viewing angles. So it's best to search for high viewing angle rather than specifically IPS.

    John
     
  9. bycicl

    bycicl Notebook Geek

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    thank you, that was kind of helpfull, but i still have some concerns.
    i would like a quality screen with nice viewing angles (IPS, PLS.......it's not for gaming).
    i'm a bit confused because there are 4 version of B156HW02 for this panel in panelook.com with different measurements, and it's not clear what version of this panel the users in the forum are talking about (http://www.panelook.com/modelsearch.php?panel_part_number=B156HW02)
    how is it possible to detect dell models that uses one panel only?

    i only mentioned IPS because i know it's not always a simple transition from TN to IPS. but i don't why.
    let's say i want to choose just ANY screen, with the same resolution. as you mentioned earlier, choosing the correct screen depends on the type of connection (display cable).
    what other things do i need to check besides that?
     
  10. bycicl

    bycicl Notebook Geek

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    doe's anyone knows what do i need to check besides the connector before choosing replacement screen for LATITUDE E5540? i want to upgrade from TN to a good wide viewing angle screen.
     
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