how to decrease laptop led backlight screen to its minimum?

Hi, I’m not sure I’m posting this in proper thread, but I didn’t found any better thread for my topic.
does anybody knows is there any possibility to switch off half of LED screen backlights?
I work a lot on my laptop. I like to work in the dark: I have a back-lit keyboard. But the screen brightness kills me!
so I wonder: if my laptop uses LED backlight of the screen, is it possible to switch off half of LED bulbs for example? This probably could be like some BIOS instruction, of something like that.
Because working in a dark doesn’t need that bright light to hit my eyes.
EVEN reduced to the lowest screen backlight it still harms my eyes.

 

If you're using XP or Vista, I'm fairly certain there's nothing you can do to the screen brightness outside of the 16 steps Dell provides in BIOS. During my short flirt with Win 7 on the E6400, I found that Win 7's power manager can actually take the screen brightness below the lowest setting found in BIOS, though it's a little buggy. You might want to try looking into that.

On the other hand, the lowest brightness offered by default is pretty dim; are you sure you're actually at the lowest brightness?

 

On a dell you usually hold the 'Fn' key and then tap the up or down arrows.

Look for a blue symbol like this on two of the keys. Holding 'Fn' and tapping the brightness keys will adjust the backlight.

 

Yes, I do have the lowest setting (using Dell controlpoint display manager or Windows power settings going from control panel or from center of support for mobile pc (not sure if I translated right, because I use Ukr version)). Also Fn+Down arrow feature used as well.
So in Vindows Vista center of support for mobile pc it says the screeen brightnes is at 0. but the screen is still hit with the light my eyes.
I realy work in a DARK room without any lights at all.

 

Fn+Down arrow feature used as well. that's actualy was a first of all try.

 

You can try to get the screen dimmer.
You can throw a resistor in after the power circuit for the screen, or you can wire it direct with an external rheostat. Both would be serious work, and it would void your warranty.

A simple solution may to get a tinted sheet of plexiglas or something to put in front of the screen to make it dimmer.

K-TRON

 

You can also use this program called Gamma Panel Control.

http://majorgeeks.com/Gamma_Panel_d2796.html

I use it in conjunction with my Aspire 8730G

 

stop working in the dark and turn on an indirect light source. This is not only better for your eyes, but also looks cool and solves your problem.

 

K-Tron you're right on the money. There are aftermarket non-permanent anti-glare/tinting films specifically for laptops. 3M corporation makes some excellent products in that area.

 

That is what I vote

 

Buy a pair of $5 sunglasses.

 

that's right the program works realy cool, but it also kills colors, as soon as i just print some text it's OK.
thanks.

That's a good way but I thoght I could be solved by some BIOS-like software

 

you may be able to do it by changing the ACPI code in the registry.

Similar to this:
http://forum.notebookreview.com/showthread.php?p=5421223#post5421223

I can help you do it.

 

thanks. this looks more like what i was looking for.
i've read that threat but didn't understood where to input all that information.
is the way you propose is to change windows registry, or is it like to wright some kind of a *.bat file? I'm not strong at all in programing, im a studying in civil & industrial building engineering.
and another question:could this damage my system?(not talking about the warranty).

 

Registry editing can crash your system(Software damage only)
Before editing it backup your registry! That way if you make a mistake you can restore the backup.

Editing the registry should not void your warranty.

 

Is it nVidia or Intel Graphics?

nVidia GPU's should have Backilght control @0x61c084

A 32bit register, write 0x80000401 where 8 is the control bit, and 401 is the MAX value, write 0x80000000 where 8 is the control bit, and 000 should run your Backlight at it's lowest setting.

I think the Intel GMA4500HD also has a Backlight control Register, but I don't know the address offhand, I'll have to look it up.

Not all notebooks use the Graphics card Registers to control Backlight, My HP does not.

The ACPI code controls it, however, some use BOTH Graphics Registers AND ACPI. In this case, the Graphics Driver may BLOCK ACPI

Code:

 Method (_BCM)

A quick edit to your DSDT may give you what you need:

Code:

Name (BCL2, Package (0x0D)
            {
                0x64, <-The first number in the package is the level of the panel when full power is connected to the machine.
                0x2E,<--The second number in the package is the level of the panel when the machine is on batteries. 
                0x14, <<-- We come here to lower this value.
                0x19, 
                0x1F, 
                0x24, 
                0x29, 
                0x2E, 
                0x34, 
                0x3D, 
                0x48, 
                0x55, 
                0x64

It looks harder than it is,

Code:

 All other numbers are treated as a list of levels OSPM will cycle through when the user toggles (via a keystroke) the brightness level of the display.

So you can Add a few lower values like this:

Code:

Name (BCL2, Package ([COLOR="Red"]0x0F[/COLOR])//We alter this to add 2 states, was 0x0D (13) now 0x0F(15 Levels)
            {
                0x64, 
                0x2E,
                [COLOR="Red"]0x04,[/COLOR] //We ADD New Levels
                [COLOR="Red"]0x09,[/COLOR] // 
                0x14, 
                0x19, 
                0x1F, 
                0x24, 
                0x29, 
                0x2E, 
                0x34, 
                0x3D, 
                0x48, 
                0x55, 
                0x64

 

To be precise, editing APCI tables and all that stuff will cause it.. editing that of your programs might not cause your programs to work.. what i don't understand is why is the OP wanting to reduce the brightness to lower than minimum? Don't ppl try to keep it as bright as possible so your can read properly?

 

I read in the dark. the lowest brightness is too much.

 

use this to extract the dsdt from the registry, it will make editing the code easy: attached