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Pixel addressing

At its core, an autostereoscopic (3D without glasses) display is a standard 2D screen with a crucial added component: an optical layer (like a lenticular lens sheet or a parallax barrier) placed on top of the pixel grid. This layer doesn't create the 3D image itself; it acts as a director, guiding the light from specific pixels to specific eyes.

Pixel addressing (also called interlacing or weaving) is the process of assigning the correct image data to the correct physical pixels on the display so that this optical layer can perform its job correctly. It's the digital foundation that makes the magic happen.

Multiple Views, One Screen​

A traditional 2D display has a one-to-one relationship where one pixel shows data for one image. An autostereoscopic display must show multiple different images (called "views") simultaneously from the same physical screen. For example, an 8-view display must send a slightly different image to your left eye, your right eye, and to six other viewing positions.

You cannot simply place these eight images side-by-side; they must be intricately combined into a single pixel array.

Interlacing (Weaving)​

Interlacing is the method of combining these multiple views by taking a thin vertical slice (often just one or a few pixel columns wide) from each view and placing them in a precise, repeating pattern across the screen.

Imagine you have 8 different views (View 1 to View 8) that you want to display.

  • Slice: Instead of showing the entire View 1, you take a very narrow vertical strip from it—just one column of pixels wide.
  • Weave: You place that single column from View 1 onto the physical display.
  • Repeat: Right next to it, you place a single column from View 2. Then View 3, and so on, until View 8.
  • Cycle: The pattern then repeats: View 1, View 2, View 3... across the entire width of the screen.

This creates a composite image on the LCD panel that looks like a chaotic set of thin, shuffled stripes to the naked eye. This composite image is called an interlaced image or weaved image.

The Role of the Optical Layer​

This interlaced image would be useless without the optical layer. The lenticular lenses or parallax barrier are precisely aligned over these pixel columns.

  • Each lens in a lenticular sheet sits over a set of interlaced columns (e.g., one lens per set of 8 pixel columns, for an 8-view display).
  • The lens refracts (bends) the light from each individual pixel column underneath it in a different direction.
  • Column 1 (from View 1) is directed to a certain viewing zone in space (e.g., where your left eye would be).
  • Column 2 (from View 2) is directed to the next viewing zone, and so on.

When you position your head correctly, your left eye sees only the light bent from the columns containing views for the left eye, and your right eye sees only the columns for the right eye. Your brain fuses these two different images into a single 3D perception.

With an eye tracked system you don't need to find the spot, because the system will do it for you, but the same principle still applies.

In conclusion, pixel addressing is the critical, behind-the-scenes process of formatting image data to work in perfect harmony with the optical hardware of an autostereoscopic display, enabling the glasses-free 3D effect.