How a Flat Panel Display Works

How a Flat Panel Display Works

How a flat panel display works can be a very abstract thought.

However, on this blog post, you’ll learn a little more than the basics.

So, here is the answer:

A flat panel display is composed of two main components, the display matrix, and the backlighting.

These two are necessary to show a picture on the screen.

Flat Panel Display Infographic

How a Flat Panel Display Works Infographic

The Display Matrix

The display matrix is composed of:

  • Horizontal polarizer
  • Vertical Polarizer

And between the horizontal and vertical polarizer you find:

The RGB mask, front electrodes, liquid crystal, and rear electrodes.

The display matrix is a sandwich of various thin sheet materials designed to control the passage of light in varying degrees, and if allowed to pass, give it a color.

If not allowed, the viewer sees the color black.

Front and Rear Polarizers

Light waves can oscillate on more than one axis.

The light that is forced to oscillate on only one axis is called polarized light.

Polarized Film

The polarized film is made by stretching a plastic-like material to lengthen its fibers, then dipping the material in iodine to further lengthen and organize the material’s fibers into a grid of darkened parallel lines that are invisible to the human eye.

Liquid Crystal

Liquid crystal is a substance in a state between liquid and solid but that exhibits the properties of both.

The liquid crystals in an LCD display are naturally twisted in form.

Front and Rear Electrodes

When the polarized light passes through the liquid crystal, it naturally follows the twisting path.

Passing an electric current between the front and the rear electrodes causing individual crystals to untwist according to the voltage level.

Altering the angle of the light waves. (“And therefore their ability to pass through the front polarizer’) controls the intensity of the light to the viewer.

RGB Color Mask

Every pixel on your screen consists of three subpixels:

Red, green and blue

Every sub-pixel has its own corresponding transistors on the front and the rear electrodes.

The transistors are called:

“Thin Film Transistor [TFT]”

Because they are printed on a very thin film for integration into the Display Matrix Sandwich.

Coloring Pixels

By controlling the intensity of the light to each sub-pixel, the human eye perceives one unified pixel of color.

The same way as mixing paints on an artist’s palette.

Pixels and their sub-pixels are so small that the human eye blends them together as one image.

The Backlighting

The backlighting is composed of:

  • Monitor frame
  • Reflector
  • Light guide
  • LED strip
  • Diffuser film
  • Prism film

Reflector

A backing sheet that reflects light out towards the viewer.

It can be made from various materials, from more metallic surfaces to white, glossy surfaces, etc.

Light Guide

Light entering the light guide layer from the sides will exit through the front.

The light guide is a sheet of plastic etched with a pattern of bumps.

The farther away from the light source the bumps are, the more their density increases, according to a diffuse equation.

LED Strip

A set of LEDs provide light for the display.

There are numerous LED arrangements.

Our example shows one strip along the bottom of the display.

Diffuser Film

The diffuser film spreads the light evenly across the screen dimensions making a solid, evenly lit square. Without this refining layer, the Light Guide’s bump pattern would be apparent to the viewer.

Prism Film

The prism film has small, angled ridges on its front-facing surface that recycle off-axis light until it is emitted at the optimal viewing angle.

The light waves either exit at the brightest angle to the viewer, or they are sent through the backlighting layers again until they exit correctly.

Expert Advice

Need assistance understanding how a flat-screen display works?

Our certified experts have the technical knowledge to provide the best possible help regardless if you have a 4K, 8K or QLED television with one of the lastest flat panel displays.