Improve LCD readability at daylight

[oayz]

Using Sansa C240 - just can't read it in bright light at all no matter whht contrast/brightness settings are. Looks like they use TV grade LCD (good black etc.) which isn't sutable for daylight. Any idea if we can do something? I would consider take hit on contrast if daylight readability could be improved. Removing polarization film?

[gevaerts]

TV grade? They just used the cheapest LCD they could get

[oayz]

By TV grade I've meant deep black and elimination of front light reflection (usually achieved but some sort of polarization film). Man, even at the brightest sunlight I can't see anything if backlight is off - great for TVs with strong backlight but for MP3 player I would rather see something no matter how bad is it (color shifts, inverse or anything). Sure iPod is great in this regard!

[bertrik]

Actually, the current version of rockbox puts the c240 LCD controller in standby and disables the LCD when the backlight is off, to save a little battery power (improves runtime).

[saratoga]

By TV grade I've meant deep black and elimination of front light reflection (usually achieved but some sort of polarization film).

 Blacks are deep because the brightness is low.  Incidently, this is why you cannot see it in daylight. 

reat for TVs with strong backlight but for MP3 player I would rather see something no matter how bad is it (color shifts, inverse or anything).  Removing polarization film?

There is no polarizing film, so you can't do that.  If you want to see better in bright light, you need a stronger backlight.

[bascule]

I presume you are using the default Cabbie theme (white text on black background)? I suspect a black on white theme may be more readable...

There's nothing much in the Wiki right now for c200s, but you could just play with the background image and foreground/background colour settings.

[oayz]

bascule, actually I'm using bold black text on white (modified gsx.wps) but I've tried white on black as well.

saratoga, I agree increased backlight is a posiible solution. Getting more efficient LED or double it (I assume it's LED, not CCFL). What makes you think there is no polarization film there? Without it screen would not look that black when BL is off. Direct light would go through LCD and than be reflected back by backlight surface (disclaimer - I'm not a LCD expect)

[saratoga]

saratoga, I agree increased backlight is a posiible solution.

For an LCD in this geometry, I believe its actually the only possible solution.  Well besides buying a new MP3 player.

What makes you think there is no polarization film there? Without it screen would not look that black when BL is off. Direct light would go through LCD and than be reflected back by backlight surface (disclaimer - I'm not a LCD expect)

The front is just plastic, there is no anti reflection coating.  Polarization is provided by the LCD panel itself.  I assume you don't mean to disable that, since doing so would obviously destroy the display.

The screen is black when the panel is off because the crystal is only birefringent when energized. 

[dreamlayers]

I thought all LCDs used polarizers.  For more information see:
http://www.pacificdisplay.com/lcd_polarizers.htm
Presumably the Sansa LCD has a transmissive back polarizer.  It might be possible to replace the polarizer with a transreflective polarizer.   However, that is probably a tricky operation which may destroy the LCD.  Replacing the backlight would be safer.