(Information courtesy: X/ @ice universe)

The First Security Gate: Micro "Louvers" (Bottom Grating)Imagine this: the light emitted by the OLED screen originally scatters in all directions (this is known as a Lambertian emission distribution).

Before enabling Privacy Mode: The first security gate is completely invisible. Because the refractive indices across all layers are exactly the same, all light passes through freely, allowing the person next to you to see the screen clearly.

After enabling Privacy Mode (Voltage ON): The liquid crystal layer instantly changes state, causing a sudden shift in its refractive index. At this moment, the microscopic grating (Diffraction Structure) carved into the surface of the first refractive layer reveals itself, acting like a series of microscopic "louvers." Those light rays trying to escape at wide angles to the left and right (the "first exit light" L1) are forced to change their path (undergoing diffraction) as they pass through these louvers, deviating from their original trajectory.

The Second Security Gate: Optical "Refraction Slopes" (Top Prism/Lens)The light rays, having had their paths scrambled by the first gate, immediately crash into the optical structure (Prism or Lens) at the top of the refractive index conversion layer. This is where the life or death of the light is decided:

The Snooper's Light (Trapped): Those wide-angle light rays originally destined for the snooper's eyes hit the prism slopes at extremely awkward angles. Because there is now a refractive index difference between the liquid crystals and the top refractive layer, this portion of light cannot penetrate the screen surface. Instead, it gets severely distorted or totally internally reflected, bouncing right back into the screen. It simply can't escape. So, to anyone sitting next to you, the screen looks completely blank.

The Owner's Light (Purified): The light rays heading straight forward (the "second exit light" L2) not only smoothly penetrate the prism slopes, but due to the optical refraction effect, their exit angle is further "squeezed" and compressed. This means the screen remains crystal clear when viewed head-on, but the effective viewing angle becomes extremely

narrow, offering perfect privacy protection.

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