| 摘要: | 本論文提出非焦式同軸望遠光學系統設計，旨在於透過數位化裝置結合望遠鏡系統模組化後的光學設計，該系統具有擷取影像與即時分享至AR系統、錄影等應用需求。本文設計光學系統為8倍角放大率的定焦系統與8~24倍角放大率的變焦系統，可以當作望遠鏡、觀察模組、偵搜系統等也可運用於鳥類、大型運動賽事、狩獵等，針對一公里以外兩公尺目標物。該光學系統架構為50毫米入瞳口徑為確保足夠的進光量，本研究也針對出瞳與入瞳的相對關係進行計算與驗證，且維持至少90mm的良視距離(Eye Relief)。非焦式同軸望遠光學系統分為物鏡系統、反轉鏡系統、目鏡系統且各系統模組化後，最後搭配數位相機系統組合為一同軸式的光學系統，其中物鏡模組分別為焦距170毫米，半視角0.75度的定焦物鏡模組與焦距170毫米~514毫米，半視角0.75度~0.25度的變焦物鏡模組，反轉鏡系統橫向放大率-2倍，目鏡系統出瞳口徑6.25毫米，焦距42.5毫米。數位相機系統採用五百萬畫素的CMOS感測器，半視角5.97度，F/#為8.7。四組光學系統分別獨立設計，並要求成像品質，光學畸變，橫向色差，波前像差，公差分析。後續接合四個系統驗證是否有達設計規格。
此外光學系統光圈(Stop)皆放置透鏡第一面上進行各模組化設計，此時物鏡上的入瞳位置等於入瞳位置為重疊關係，透過出入瞳之物像關係後計算良視距離，計算後初階值代入光學軟體去做光學設計。且於初階規格無誤狀況下設計完後進行分析波前像差及成像品質，而數位相機接續非焦式同軸望遠光學系統，將數位相機的光圈至於相機第一面上，並與目鏡系統相同大小的半視角，這作法是為了能讓光線皆可順利入射至相機系統之中。最終在個模組對接後，在空間頻率50 lp/mm時MTF也大於0.4。
;This paper presents the design of a coaxial afocal telescope optical system that integrates a modularized telescope architecture with digital imaging devices. The proposed system is intended to support image acquisition, real-time sharing to augmented reality (AR) systems, and video recording applications. Two optical configurations are developed: a fixed-focus system with 8× angular magnification and a zoom system providing 8×–24× angular magnification. The system can be employed as a telescope, observation module, or reconnaissance system, and is suitable for applications such as bird watching, large-scale sporting events, and hunting, with a design target of resolving a 2 m object at distances exceeding 1 km.
The optical architecture adopts a 50 mm entrance pupil diameter to ensure sufficient light-gathering capability. The relative relationship between the entrance pupil and exit pupil is calculated and verified, while maintaining a minimum eye relief of 90 mm. The coaxial afocal telescope system is modularized into an objective lens system, an erecting lens system, and an eyepiece system. After modular integration, a digital camera system is coupled to form a complete coaxial optical system. The objective lens module includes two configurations: a fixed-focus objective with a focal length of 170 mm and a half field of view of 0.75°, and a zoom objective with a focal length range of 170–514 mm and a half field of view ranging from 0.75° to 0.25°. The erecting lens system provides a lateral magnification of −2×, while the eyepiece system has an exit pupil diameter of 6.25 mm and a focal length of 42.5 mm. The digital camera system employs a 5-megapixel CMOS sensor with a half field of view of 5.97° and an F-number of 8.7.All four optical subsystems are designed and optimized independently, with performance requirements including imaging quality, optical distortion, lateral chromatic aberration, wavefront aberration, and tolerance analysis. The four subsystems are subsequently integrated and evaluated to verify compliance with the design specifications.
In the modular optical design, the aperture stop of each subsystem is placed on the first surface of the corresponding lens. Under this configuration, the entrance pupil location of the objective lens coincides with the aperture stop. Based on the entrance–exit pupil imaging relationship, the eye relief is calculated, and the initial design parameters are introduced into optical design software for system optimization. After confirming that the preliminary specifications are satisfied, wavefront aberration and imaging performance analyses are conducted. The digital camera system is then coupled to the coaxial afocal telescope, with the camera aperture placed on the first surface of the camera lens and matched to the same half field of view as the eyepiece system. This configuration ensures efficient light coupling into the camera system. In the final integrated configuration, the modulation transfer function (MTF) remains greater than 0.4 at a spatial frequency of 50 lp/mm. |
