| dc.description.abstract | This projection lens design consists of 4 glass spherical lenses and 3 plastic aspherical lenses. The focal length of the lens is 20.458 mm, with a diagonal field of view of 65 degrees and a horizontal field of view of 48.50 degrees. The aperture is located on the first lens surface with an entrance pupil diameter of 10 mm, resulting in an F-number of 2.046. The angular resolution is set at 45 PPD (Pixels Per Degree), corresponding to a spatial frequency of 60 lp/mm.
The lens is designed for use with a 1.03-inch OLED panel, which has a resolution of 2560 x 2560 pixels and a pixel size of 7.2 µm x 7.2 µm. In this study, it was derived that the lens design can be developed independently without considering the influence of the waveguide, as all Seidel aberrations of light within the waveguide are zero and independent of its material and thickness.
The emitting surface of the panel is located at the projection lens′s object focal plane. The function of the projection lens is to project the panel image through collimation onto the first holographic element. The light then undergoes total internal reflection through the waveguide, passing to the next holographic element, and finally reaching the eye for viewing. In the MR (Mixed Reality) system, the projection lens acts as a magnifier with a magnification factor of 12.22 times.
After passing through the projection lens, any television distortion and lateral chromatic aberration in the panel image are magnified accordingly. Linear discrimination rate and lateral chromatic aberration discrimination rate are used for analysis. The designed linear discrimination rate and lateral chromatic aberration discrimination rate of this projection lens are 0.412 and 0.675, respectively, both less than the human eye′s discrimination threshold of 1. Therefore, the human eye cannot perceive linear distortion or lateral chromatic aberration, meeting the design requirements. | en_US |