Optimized design of Capsule endoscopy lens based on ZEMAX

At present, the application of Capsule endoscopy (CE) faces some extremely important issues, e.g., image quality and field of view, which causing difficulties for doctors to make an accurate diagnosis. It\´s a technical difficulty to acquire wide-angle internal intestinal image under the volume restrictions of CE. In this paper, a simple and practical design of CE lens aimed to clearer and wider-angle intestine image is proposed based on ZEMAX. The new lens improves the field curvature and distortion with the application of special transparent cover and aspheric technology. The optimal design has a FOV of 105 °, and the F number is 2.8. The modulation transfer function (MTF) is about 40% at 45 lp/mm, and the distortion is under 15%. It can perfectly satisfy the requirements of the CE lens, and provide high-quality image for 1/4" CMOS image sensor with effective pixels of 1600×1200 and pixel size of 2.2 μm.