Bare-eye 3D projection technology

　　Those who have watched 3D movies in theaters have all experienced the process of receiving special glasses from the staff. This is fine for those who don't wear glasses, but for those who already wear glasses, it might not be so comfortable. Wearing another layer of glasses over their existing ones is quite uncomfortable on the bridge of the nose. Autostereoscopic 3D projection Technological advancements have freed humanity from the constraints of 3D glasses.

　　Autostereoscopic 3D projection technology is a technique that reproduces three-dimensional images of objects by recording the amplitude and phase distribution of light waves on photographic film or plates. Holographic technology achieves 3D visual effects by recording all the information (amplitude, phase) in the light waves reflected (or transmitted) by the photographed object. The process is mainly divided into two steps:

　　The first step is to record the object's light wave information using the principle of light interference, i.e., shooting. Under the irradiation of a laser, the photographed object forms a diffusely reflected object light beam. Another part of the laser, as a reference light beam, is projected onto the holographic film, superimposed on and interfering with the object light beam, converting the amplitude and phase at each point of the object light wave into the intensity of light waves changing in space. Thus, using the spacing and contrast between interference fringes, all the spatial information of the object is recorded. After the film recording the interference fringes is processed through procedures such as development and fixing, it becomes a Denisyuk hologram, also known as a hologram.

　　The second step is to reproduce the object's light wave information using the principle of diffraction, i.e., imaging. The hologram formed in the first step is like a complex grating. Under coherent laser irradiation, the diffraction light wave of a linearly recorded sinusoidal hologram generally gives two images, namely the original image and the conjugate image. After the superposition of the two images, a realistic visual effect is obtained, which is Autostereoscopic 3D projection the principle of the technology.