Wide Field-of-View, High-Resolution Endoscopic Lens Design with Low F-Number for Disposable Endoscopy

Abstract

In the past few decades, video endoscopy has become one of the primary medical devices in diverse clinical fields for examination, treatment, and early disease diagnosis of the gastrointestinal tract. For an accurate diagnosis, an endoscopic camera offering bright and wide field-of-view images is required while maintaining its compact dimensions to enter the long, narrow, and dark tract inside of the body. Recent endoscopic lenses successfully provide wide fields-of-view and have compact sizes for the system; however, their f-numbers still remain at 2.8 or higher. Therefore, further improvement in f-numbers is required to compensate for the restricted illumination system of the endoscopic probe. Here, we present a low f-number endoscopic lens design while providing wide field-of-view and high-resolution imaging. The proposed lens system achieved a low f-number of 2.2 and a field-of-view of 140 deg. The modulation transfer function (MTF) is over 20% at 180 lp/mm, and relative illumination is more than 60% in the full field. Additionally, the proposed lens is designed for a 1/4” 5-megapixel complementary metal-oxide-semiconductor (CMOS) image sensor with a pixel size of 1.4 µm. This all-plastic lens design could help develop a high-performance disposable endoscope that prevents the risk of infection or cross-contamination with mass manufacture and low cost.

Wide field-of-view metalens: a tutorial

“…The challenge is exacerbated for WFOV endoscopes, which involve complex compound lenses or lens arrays with an even larger footprint 132 – 134 …”

“…The challenge is exacerbated for WFOV endoscopes, which involve complex compound lenses or lens arrays with an even larger footprint. [132][133][134] To address the issue, Liu et al adapted the doublet metalens design to create a meta-objective that can be used in conjunction with a fiber bundle microscope for endoscopy imaging. 131 Ray-tracing simulation results shown in Fig.…”

Injection molding of high-precision optical lenses: A review

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