01 · Backlit lineage
LCD & the shutter
An LCD never makes its own light. One backlight glows white behind the whole screen, and every pixel is a tiny shutter that decides how much of it gets through. Twist the crystals one way and light passes. Twist them back and it's blocked. That single trick, copied across millions of pixels, is the entire panel. The catch shows up in every dark scene: a shutter can dim light, but it can't fully stop it.
The crystals sit in a quarter twist and rotate the backlight just enough to line up with the front filter. Light pours through and the picture is bright. Drag the voltage up to shut it down.
Station 01
Build the stack
An LCD is a sandwich. Seven layers, back to front, each doing one job. Pull the stack apart, drag to spin it, then tap a layer or step through with the arrows to follow the light from the backlight out to the glass.
Drag the slider to pull the sandwich apart. Tap a layer, or step through with the arrows, to follow the light from the backlight out to the glass.
Station 02
Mix one pixel
A white backlight hits three color filters: red, green, blue. The crystal shutter sets how far each one opens, and your eye blends them into a single color. Drag the sliders and build one.
Slide all three to zero. The patch still isn't truly black, and that faint glow is the backlight leaking through the closed shutters.
Station 03
Why black glows
Drag the bright spot around a dark room. The backlight behind it can't switch off for just one pixel, so light spills into a halo and the black around it lifts to gray. This leak is the flaw every backlit screen after LCD is trying to fix.
The tradeoff
What LCD nails, and what it can't
The shutter trick is cheap, bright, and lasts for years. The price is black that never gets all the way to black.
Strengths
- Cheap to build at huge scale, which is why most screens are still LCD.
- Gets very bright, great for sunny rooms and HDR highlights.
- Can't burn in, because the pixels don't age unevenly the way self-lit ones do.
Weaknesses
- Black looks dark gray in a dim room, because the backlight leaks.
- Lower contrast than anything that lights its own pixels.
- Thicker, since it stacks a backlight, diffuser, and filters.
Questions
LCD, quick answers
How does an LCD make color?
The backlight is white. Every pixel splits into three subpixels behind red, green and blue filters. The crystal shutter sets how far each subpixel opens, and your eye blends them into one color. All three open looks white, all three shut looks near black.
Why isn't LCD black truly black?
The backlight is one sheet that's always on. The crystals can twist to block most of it, but not all of it. A little always slips through, so in a dark room black reads as dark gray. Local dimming helps by lowering the backlight behind dark areas, but it works in zones, not per pixel.
Is an “LED TV” different from LCD?
No. An LED TV is an LCD. The only thing “LED” describes is the backlight, which switched from old fluorescent tubes to LEDs. The panel still works by twisting crystals to block light.