How do 3D glasses create a three-dimensional effect?

There are actually many types of 3D glasses, but the principle of creating a three-dimensional effect is the same.

The reason why the human eye can feel the three-dimensional sense is because the left and right eyes of the human are facing forward and arranged horizontally, and there is a certain distance between the two eyes (usually the average distance between the eyes of an adult is 6.5cm), so Two eyes can see the same scene, but the angle is slightly different, which will form the so-called parallax. After the human brain analyzes the parallax, it will get a stereoscopic feeling.

You put a finger in front of your nose and look at it with your left and right eyes, and you can feel the parallax very intuitively.

Then we only need to find a way to make the left and right eyes see two pictures with parallax of each other, then we can produce a three-dimensional effect. Humans discovered this principle hundreds of years ago. The earliest three-dimensional images were made by hand-painting two horizontally arranged images with different angles, and a board was placed in the middle. The observer's nose was attached to the board, and the left and right eyes were Only the left and right images can be seen respectively. The partition in the middle is essential, it ensures that the pictures seen by the left and right eyes do not interfere with each other, which is the fundamental principle of 3D glasses.

In fact, watching 3D movies requires a combination of glasses and a playback device. The playback device is responsible for providing two-way picture signals for the left and right eyes, while the 3D glasses are responsible for delivering the two signals to the left and right eyes respectively.