本投影鏡頭設計由4片玻璃球面鏡片與3片塑膠非球面鏡片所組成，鏡頭焦距20.458 mm，對角線全視角65，水平方向全視角48.50，光圈位於鏡頭第一面上，入瞳大小為10 mm，F/#=2.046，設定角度解析度為45 PPD，則空間頻率為60 lp/mm。使用1.03吋、長寬比相同OLED面板，畫素數目為25602560，單一畫素大小為7.2 m7.2 m。由於本文推導出光在波導內追跡其所有賽德像差為零且與波導的材料與厚度無關，所以投影鏡頭可以單獨設計，不需要考慮波導的影響。面板發光面位於投影鏡頭物焦平面，投影鏡頭功能是把面板影像經由投影鏡頭準直投射至第一個全像元件，透過全像元件使光線在波導內進行全反射傳遞到下一個全像元件，最後經由眼睛觀看。而投影鏡頭在MR系統中可以被視為一個放大鏡，角放大率為12.22倍。當面板影像經過投影鏡頭後，其電視畸變與橫向色差會隨著影像一同被放大，我們利用直線鑑別率與橫向色差鑑別率來分析。本文投影鏡頭設計直線鑑別率與橫向色差鑑別率分別為0.407和0.675，都小於人眼辯別率1，因此人眼無法辨識其直線扭曲與橫向色差，而達到其設計要求。;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.
