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How can I convert a transmissive to a reflective LCD screen?

Hello everyone,

So basically a reflective LCD screen is one that has no backlight, and reflects ambient light off a type of mirror reflector, to allow the image on the LCD to be seen via reflection. An example of a reflective LCD screen is the Gameboy Advance's LCD screen.

A transmissive LCD is one that has a backlight that transmits light, but does not reflect light. These are typically 99.99% of the screens out there, such as PC Monitors, Smartphone screens, etc...

Now I would like to know how to turn a Transmissive LCD screen, into a Reflective screen, like the GBA screen, without the need for a backlight. The reason I ask this is because I need it for outdoor use (to be sunlight readable), and backlights can't compete with the sun, and having a strong backlight drains battery.

I have done a lot of research on this, but can't wrap my head around how the GBA screen works.

I have removed the backlight off my computer LCD screen, and added a reflective film beneath the rear polarizer on the LCD screen, but it obviously doesn't make it reflective. I'm obviously missing a crucial step.

Is the reflective film in the GBA, 'sandwhiched' somewhere in between the actual LCD screen?

Does anyone know how to make a Transmissive LCD computer monitor, into a Gameboy Advance Reflective Screen?

rickharris11 months ago

You need a 2nd polerising leyer see image.

working-of-lcd.gif
davidwinst (author)  rickharris11 months ago

The TN LCD Display that I used already has 2 polarizing films, exactly like your diagram above. I tried adding a normal mirror, and aluminum foil exactly like your diagram shows, but it still does not reflect the light. If it does reflect light, it probably only reflects a very low amount of light, because the screen is not readable.

-max-11 months ago

I don't think it would be possible to modify an existing LCD to work like this. Best case it will work but not well. The LCDs used by watches and original gameboy's is very different from the advanced TN and IPS LCD panels used by most computer screens. There does exist commercial LCD panels called "Sunlight readable" screen designed to work in direct sunlight for niche applications.

If you want, you can read what answers I got for a simalar question:

https://www.instructables.com/answers/easily-viewab...

davidwinst (author)  -max-11 months ago

Yes, I know about the 'Sunlight Readable' screens. They are called Transflective screens. I have a few Transflective LCD screens on some laptops, but they are a compromise between Transmissive and Reflective, so they only partially reflect ambient light. They work really well outdoors, but when compared to my GBA screen, they are a bit dimmer, which is why I need Reflective instead of Transflective. They are good screens, but Reflective is the way to go for the best readability and contrast of the screen.