Most of the naked-eye 3D technology is in the research and development stage. Its research and development are divided into two directions, one is the research and development of hardware equipment, and the other is the research and development of display content processing. The second type has already begun small-scale commercial applications. Not much contact with mass consumers. From a technical point of view, naked-eye 3D can be divided into four types: Barrier, Lenticular Lens, Directional Backlight, and Direct Imaging. The biggest advantage of naked-eye 3D technology is that it gets rid of the shackles of glasses, but there are still many shortcomings in terms of resolution, viewing angle, and viewing distance.
From a technical point of view, naked-eye 3D can be divided into three types: Barrier, Lenticular Lens and Directional Backlight.
Light barrier 3D technology is also called parallax barrier or parallax barrier technology. Its principle is similar to polarized 3D. It has been successfully researched by engineers from Sharp’s European laboratory for more than ten years. Light barrier 3D products are compatible with the existing LCD liquid crystal technology, so they have advantages in mass production and cost, but the image resolution and brightness of products using this technology will decrease. The realization method of light barrier 3D technology is to use a switch liquid crystal screen, polarizing film and polymer liquid crystal layer, using the liquid crystal layer and polarizing film to create a series of vertical stripes with a direction of 90°.
Barrier technology: These stripes are tens of microns wide, and the light passing through them forms a vertical thin grid pattern, which is called “parallax barrier.” This technology makes use of the parallax barrier placed between the backlight module and the LCD panel. In the stereoscopic display mode, when the image that should be seen by the left eye is displayed on the LCD screen, the opaque stripes will block the right eye; for the same reason, When the image that should be seen by the right eye is displayed on the LCD screen, the opaque stripes will block the left eye. By separating the visible images of the left eye and the right eye, the viewer can see the 3D image.
Advantages: Compatible with the existing LCD liquid crystal technology, so it has advantages in mass production and cost.
Disadvantages: The screen brightness is low, and the resolution will decrease inversely as the display increases at the same time.
Lenticular lens technology is also called lenticular lens or micro-cylindrical lens 3D technology, and its biggest advantage is that its brightness will not be affected. The principle of the cylindrical lens 3D technology is to add a layer of cylindrical lens in front of the liquid crystal screen, so that the image plane of the liquid crystal screen is located on the focal plane of the lens, so that the pixels of the image under each cylindrical lens are divided into several sub-pixels. This way the lens can project each sub-pixel in a different direction. Therefore, when both eyes look at the display screen from different angles, they can see different sub-pixels. However, the gap between pixels will also be enlarged, so sub-pixels cannot be simply superimposed. Let the cylindrical lens and the pixel column not be parallel, but at a certain angle. In this way, each group of sub-pixels can repeatedly project the viewing zone instead of only projecting a group of parallax images.
Lenticular lens (Lenticular Lens) technology schematic diagram The reason why its brightness will not be affected is because the lenticular lens will not block the backlight, so the brightness of the picture can be well protected. However, since its basic principle of 3D display is still similar to the parallax barrier technology, the resolution is still a more difficult problem to solve.
Advantages: 3D technology display better, the brightness is not affected
Disadvantages: Related manufacturing is not compatible with the existing LCD liquid crystal technology, and new equipment and production lines need to be invested.
3M’s pointing light source 3D technology: 3M has invested a lot of energy in the directional backlight 3D technology. The Directional Backlight 3D technology is paired with two sets of LEDs, and the fast-response LCD panel and driving method are used to make The 3D content enters the viewer’s left and right eyes in a sequential manner to exchange images to generate parallax, and then let people feel the 3D three-dimensional effect. Not long ago, 3M company just demonstrated its successfully developed 3D optical film. The interview of this product realized that the real three-dimensional images can be displayed on mobile phones, game consoles and other handheld devices without wearing 3D glasses, which greatly enhanced Communication and interaction based on mobile devices.
Advantages: The resolution and light transmittance can be guaranteed without affecting the existing design framework, and the 3D display effect is excellent.
Disadvantages: the technology is still under development and the product is immature