为了研究外界因素,如人工光阑偏心和轴外物点所引入人跟横向色差的变化规律,构建了个体眼模型。由角膜地形图计算了8只人眼视轴与光轴的夹角。依据实际测得的角膜地形图数据、人眼波像差、眼轴数据以及计算的视轴与光轴间夹角,运用ZEMAX光学设计软件构建了考虑视轴方向的个体化眼模型。基于这些眼模型,研究了外置人工光阑相对视轴偏移在中心凹附近所引入的横向色差变化规律,讨论了在420~700nm边缘横向色差随入射视场角的变化规律。研究表明,横向色差随人工光阑的偏移量线性增加,增加的速率为5.46~5.95(’)/mm,平均值为5.7(’)/mm,但8只人眼存在一定的个体差异。在鼻侧和颞侧20°视场范围内,8只人眼的横向色差平均以0.36(’)/(°)的速率随视场角增加而增加,不同个体的增长速率有所差别,变化范围为0.32~O.44(’)/(°)。另外,横向色差在长波段的变化要比短波段处缓慢。由于横向色差随外置光阑偏移和视场有较大的增长,因此,在视网膜成像系统和现代头盔系统的设计中应当考虑横向色差的影响。
In order to study the variation of Transverse Chromatic Aberration (TCA) with external factors, such as the displacement of artificial pinhole from the visual axis and eccentricity,this paper constructs individual eye models to investigate the characteristic of TCA. The angle between visual axis and optical axis is calculated from the cornea data for eight eyes. According to the measurements of the corneal surfaces, optical axis lengths, wavefront aberrations and the angle obtained from calculation, the individual eye models involving the angle between visual axis and optical axis are constructed with ZEMAX software. The constructed eye models are then used to investigate the variations of TCA at the fovea with the displacement of artificial pinhole from the visual axis and to analyze the var-iation of TCA with the eccentricity over spectra from 420 nm to 700 nm. The result shows that the TCA increases with the displacement linearly at an average ratio of 5.7(')/mm, but there are some differences among the eight eyes over the range from 5.46(')/mm to 5.95(')/mm. Across the field of view of 20° both at nasal and temporal,the TCA increases with the eccentricity atan average ratio of 0.36'/(°) for the eight eyes over the range from 0.32(')/(°) to 0.44(')/(°). Furthermore, the variation of TCA is slower at the end of long wavelength than that at the end of short wavelength. It is concluded that the influence of TCA should be considered in the designs of retina imaging systems and modern head-mounted display systems.