Resolution and number of views are the key parameters of 3D display devices, which determine the 3D display effect and the market acceptance of 3D display devices. Therefore, it is also a very concerned parameter for researchers and manufacturers. The researchers and manufacturers have improved the resolution and view number of the 3D display in terms of timing display, display panel design, backlight design and so on.
Figure 6 shows the schematic diagram of a time-series aperture high resolution 3D display technology, which is developed by the University of Cambridge. The display uses the LCD shutter as the timing control aperture in the prism array, and then guides the light emitted from the display at different times to different locations. Therefore, the resolution of the 3D image is the same as that of the 2D display. However, the technology scheme has a high demand for refresh rate of 2D display. In this experiment, the refresh rate of CRT display is as high as 1000Hz.
Figure 7 shows the schematic diagram of high pixel density high resolution 3D display technology, which is developed by the Japanese NLT technology company (original NCE liquid crystal technology). The technology divides the vertical single pixel into N sub pixels, and uses special lens array to guide the light emitted from each sub-pixel in the original pixel to different viewing angles, so that the resolution of 3D image is the same as that of 2D image. In May 2013, NLT implemented a high resolution 3D display with 2 perspectives and 6 perspectives, with a display panel of 7.2 inches.
Figure 8 shows the schematic diagram of the special backlight design resolution 3D display technology, which is developed by the 3M company. The display includes two LED light sources, specially designed light guide plate, reflective film, 3D film (nano level microlens and micro prism), and a liquid crystal panel that can be quickly switched. This technique can be left / right eye light emitted from the light guide to the left / right eye respectively through the light guide plate and 3D film with special design, the use of liquid crystal panel on light intensity modulation, and then, when the left and right light source are open, left and right eye can in turn get full resolution images, through the human fusion form 3D image.
Figure 9 shows the schematic diagram of a high resolution 3D display technique for multiple projection ceremonies. The technology uses multiple projectors, scattering screens and two parallax barriers with the same pitch.
The first level parallax barrier is controlled by the light from each projector to the specific location of the scatterscreen. The second level parallax barrier controls the direction of the light emission on the scatterscreen and makes the light originating from the same projector converge in the same place.
Therefore, every projector produces a perspective. However, the price of the system is very expensive because of the use of multiple projectors.
Although the above technology implements multiple perspectives, the angle of view is located on one side of the 3D image. However, the angle of the actual object is 360 degrees. In order to make the 3D image have a 360 degree view, the Shunsuke Yoshida of Japanese intelligence communication research institute used many projectors around the circle and an anisotropic cone.
The shape backdrop screen made the 3D display named fVision.
Figure 10 shows the schematic diagram of the display device. From the picture, we can see that both the projector and the conical rear projection screen are placed under the desktop, and the conical rear projection screen has parallax images in horizontal direction. The technology implements a 5cm high full color image suspended on the desktop, and the image has an effect map of the 3D image obtained from a 360 degree angle, as shown in Figure 11.