3D Display Techniques: From Glasses to Holograms

A 3D display is a type of display device that presents three-dimensional images by simulating the principle of binocular parallax in human eyes. Compared with ordinary 2D displays, it can break through the flat – screen limit, making the images appear three – dimensional and lifelike, allowing viewers to obtain an immersive visual experience.

Working Principle

The sense of 立体感 in 3D images is derived from the slight differences in the images seen by the left and right eyes. When the human 双眼注视 an object, due to the approximately 6 – 7 cm distance between the two eyes, the images seen by the left and right eyes are slightly different. These two 2D images with slight differences are synthesized by the brain to present a sense of three – dimensionality. 3D display technology utilizes this principle. During the shooting process, the camera mimics the human 双眼，and the left and right lenses respectively shoot two 2D images with slight differences. When watching a 3D image, various technologies are used to ensure that the left eye can only see the image shot by the left lens of the camera, and the right eye can only see the image shot by the right lens of the camera. These two images are then synthesized by the brain to generate a 3D image.

Main Types

Glasses – type 3D Display:
- Anaglyph 3D: Also known as color – difference 3D, it uses passive red – blue (or red – green, red – cyan) color – filtering 3D glasses. This technology is the oldest, with a simple imaging principle and low cost. However, the 3D image effect is the worst, and color fringing is likely to occur at the edges of the image.
- Polarization 3D: It uses passive polarizing glasses. This technology divides the original image into two groups of images, vertical – polarization and horizontal – polarization light, according to the principle that light has a “vibration direction”. The left and right lenses of the 3D glasses use polarizing lenses with different polarization directions, so that the left and right eyes of people can receive two groups of images, which are then synthesized into a 3D image by the brain. This technology is widely used in cinemas, but it requires a high – brightness display device and will halve the screen resolution.
- Active Shutter 3D: It uses active shutter 3D glasses. By increasing the refresh rate of the screen, the image is divided into two groups of images corresponding to the left and right eyes and displayed alternately. At the same time, the infrared signal transmitter synchronously controls the opening and closing of the left and right lenses of the shutter 3D glasses, so that the left and right eyes can see the corresponding images at the correct time. This technology can maintain the original resolution of the image, but the 3D glasses are more expensive, and there are problems such as image flicker and reduced brightness.
Naked – Eye 3D Display:
- Parallax Barrier: It uses optical elements such as parallax barriers or lenticular lenses to directly present 3D images, eliminating the need to wear glasses. However, it still has limitations in terms of resolution, viewing angle, and viewing distance.
- Volumetric Display: It forms 3D images by displaying a series of 2D images at different angles in space.
- Holographic Display: It records and reconstructs the phase of the object light wave to achieve 3D scene reconstruction, which can provide a more realistic 3D visual effect.

Application Fields

Education: 3D displays can be used to create immersive teaching scenarios, such as virtual laboratories, virtual tours, etc., making teaching more vivid and interesting.

Film and Television: 3D technology is widely used in movie production and screening, such as the movie Avatar, which brought 3D technology to a new high. In addition, some TV programs and online video platforms also began to provide 3D content.

Gaming: 3D displays can provide gamers with a more immersive gaming experience, allowing them to feel as if they are in the game world.

Medical: 3D displays can be used for medical imaging, such as 3D ultrasound, 3D CT, etc., helping doctors to more accurately diagnose diseases. In addition, 3D displays can also be used for surgical simulation and remote diagnosis.