Beiträge von hoarpad

  • DELL U2412M: Neuer ergonomischer Büromonitor auch zum Spielen bestens geeignet

    Zitat von Denis


    Screens with CCFL backlight also use PWM to control brightness. There are good reasons to implement this approach with LED backlights too (e.g. high range of regulation and no color shifts) instead of pure current adjustment.


    Best regards


    Denis


    Yes I know. But the PWM cannot switch off CCFL entirely during one switching cycle, because it is not as fast as LEDs. LEDs are much, much faster so they flicker brutally compared to CCFL if they are switched on and off repeatedly. That is why so important for our health the exact solution of backlight-controlling, if we are speaking about LED backlights.

    Best wishes

    Árpád

  • DELL U2412M: Neuer ergonomischer Büromonitor auch zum Spielen bestens geeignet

    Dear Sir or Madam,

    First of all congratulation to your tests. This is the best monitor testing site I have ever seen.


    I would like to ask you a little bit more detailed question about the LED backlight of the new DELL U2412M.


    (Sie können aber deutsch antworten weil ich alles auch in deutsch verstehe, aber es ist schwer für mich deutsch zu schreiber. Danke)


    I am to buy an IPS DELL monitor. I have two potential candidates, the DELL U2311H and the new coming DELL U2312HM which will have LED backlight, as the DELL U2412M has..


    But, what I am afraid of is the PWM control (Pulse Width Modulation) of the new LED backlight technology.


    There are a lot of sites on the net which say, that the high- or not-so-high-frequency flickering of the LEDs (due to this PWM LED control) can cause serious eyestrain, or even worse, migraine, even if you cannot see it at first glance, at all. You can read an example here . Another man here could not stand his newly purchased LED backlight monitor, sent it back to the shop and went back to CCFL. I have not found any test site yet, which tried to investigate this problem of the new technology.


    If there is any possibility please help the people with oversensitive eyes, in their decisions, and try to answer the following questions in your monitor tests.


    1. Does the tested monitor have a PWM or a DC backlight control?
    2. If it has a PWM, what frequency does it operate on?
    3. Is there any solution to switch it off or lower the effect?
    4. And please try to find a parameter to evaluate the intensity of the flickering.


    Thank you for your help for advance.
    Vielen Dank für Ihre Hilfe.


    Yours sincerely


    Árpád Honyák
    from Hungary