While there is a plethora of new innovation taking place in head mounted displays, the pace at which the desktop type displays that are used to showcase 3D also called glasses free 3D displays or light-field displays or lenticular displays almost have a fundamental principle that has not changed in decades. In this blog post we give a visual understanding of how the glasses free 3D displays work.
You must have seen the museum cards which show different sides when tilted. They used to be earlier available only in 2 different views but now are available in multiple more views that are more fine grained. These cards are basically showcasing how almost all the glasses free 3D displays work, by overlaying a layer of thin lens / vertical stripes that block underlying views to show different views as you change your angle of viewing. The video below explains it better.
In such displays in static pictures use case multiple pictures are vertically striped and each view is set next to each previous view. So imagine if you have two views that you see as you change your angle of viewing, you will take two pictures and cut strips of each picture vertically in equal length and put them next to each other alternatively, so the first strip from first picture appears in the first column, then the first strip of the second picture appears in the second column, then second strip of the first picture appears in the third column, and then the second strip of the second picture appears in the fourth column and repeat this pattern until all the strips of both pictures are covered by putting them next to each other.
Then you take a lenticular sheet where there are strips that are of width exactly matching the width of each pictures strip width and lay it carefully, so alternate lenticular strip shows only one view and as you move your head, you see the alternate strip.
The lenticular strip thus blocks alternate views by only allowing the strip below the current strip you are looking at. If you make the strips go narrower, and add more pictures you have a more fine resolution 3D experience.
If you repeat the same logic for a moving picture where multiple views are hidden behind lenses layered on top of a LCD panel, you get a multi-view 3D experience for displays. However, as you are limited with the base resolution of the LCD, each additional view introduces less resolution for each individual view, thereby making the views have less resolution as you add more views.
By adding a bit more fine tuned lens structure of overlay lens array the same principle is called lightfield display. Almost all the glasses free 3D display that exists in the market use the same principle. Some do it a bit better than other, but almost all need very high resolution at the base if the individual views need to have higher resolution. So that's it. This is how the glasses free 3D works.