A new volumetric 3D display using multi-varifocal lens and high-speed 2D display

We have developed a new volumetric 3-D display using the multi-varifocal lens and high-speed 2-D display. Floating clear 3-D image in space can be successfully obtained. Our volumetric 3-D image is composed of many 2-D layered images by using multi-varifocal lens. Many 2-D images can be layered by changing their depth position using the discrete focal length change of multi-varifocal lens. The high-speed multi-varifocal lens is composed of several sets of a birefringent lens and a polarization switching device. The total lens power is the sum of the lens powers of these sets. The number of lens sets, N, can yield 2N variations of total focal lengths. In order to re-position many 2-D images within afterimage time, high-speed 2-D display is newly constructed by compact projector array using LED light sources. These projector images are projected to the same position of one screen. By switching these projectors quickly, 2-D images on the screen can be displayed at high-speed. This high-speed 2-D display can successfully provide bright and clear 2-D layered images by using point light sources of LED.