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str4ngS
Paper Tape
Posts: 9
Registered: ‎11-13-2010
Location: Romania
Views: 728
Message 1 of 5

LED display disturbingly flickers at lower brightness

Dear Forum Members,

I have recently bought a notebook, Lenovo G550L with a LED-backlit display model BOEHydis HT156WXB-100 (according to Everest 5.02 by Lavalys). I am kind of satisfied with the computer itself, but there is one thing that really gives me tough time. If I adjust the backlight brightness to a level other than maximum, it controls the brightness of the LED-backlight using visibly Pulse-Witdh Modulation at very low frequencies depending on desired brightness. If I want to spare power or am on a dark place or it's night, I always turn it down otherwise its brightness is kind of blinding my eyes, at the same time these low frequencies with PWM causes my eyes to strain and sometimes I feel moderate headache on the side. I'm looking for a solution to alter the method of my LED-blacklight or raise the PWM frequency.

 

I tried to address BOEHydis (now Hydis) with the problem in e-mail. I was referred to BOE by a Hydis representative, who wrote me that BOEHydis don't exist together anymore. With his help I could find BOE's new website and found this product on it. I sent them a letter too, but haven't gotten an answer yet.


The display itself appears in Windows' (XP, SP3) device manager as a standard Plug and Play monitor. My question is that is there any software (or even hardware) solution or a more advanced alternate driver for this type of screen that I can raise PWM frequency or somehow alter the method of adjusting brightness?

Thanks in advance,

str4ngS

str4ngS
Paper Tape
Posts: 9
Registered: ‎11-13-2010
Location: Romania
Views: 669
Message 2 of 5

Re: LED display disturbingly flickers at lower brightness

Anyone here?

Retired Moderator
Retired Moderator
Posts: 13,719
Registered: ‎12-07-2009
Location: CZ
Views: 659
Message 3 of 5

Re: LED display disturbingly flickers at lower brightness

noise at lower brightness?

have you ever checked the issue under linux?

do you have valid warranty?


http://www.krasotaiskusstva.com
str4ngS
Paper Tape
Posts: 9
Registered: ‎11-13-2010
Location: Romania
Views: 648
Message 4 of 5

Re: LED display disturbingly flickers at lower brightness

There is no noise at lower brightnesses. There is flickering coming from the working principle of the unit that actually adjusts brightness (pulse width-modulation, PWM). Of course, I have tried it on various OSes, Windows XP, Windows 7, Ubuntu Linux, Debian Linux, Knoppix etc. This is nothing to do with the operating system. I am just hoping there is a driver that could override the way it adjusts its brightness (PWM). Raising the PWM frequency would be a solution but I don't know how the hell I should tell the circuit to do that.

 

Although I have valid warranty, this is not a malfunction, rather a quicky and silly realization of PWM that kills the human eye caused by oligarchies like BOE (who designed and made it) and Lenovo (who selected it) willing to spare their extra-profit and not to design something well and permanently good. Along with this they almost shoved the display back to a quality and side-effects of a CRT.

Retired Moderator
Retired Moderator
Posts: 13,719
Registered: ‎12-07-2009
Location: CZ
Views: 644
Message 5 of 5

Re: LED display disturbingly flickers at lower brightness

contact lenovo support line and ask for lcd replacement.

( as i know some lcd panels may have similar issue like you have )


http://www.krasotaiskusstva.com

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