A 1.8 mm-Diameter Chip-on-Tip Endoscope with Integrated µLED Illumination for Narrow-Cavity Imaging

Advances in microelectronics have driven the miniaturization of endoscopic systems, leading to increasingly compact devices with enhanced optical and electronic performance. However, the current state-of-the-art commercial endoscopes-typically ranging from several millimeters to over 1 cm in diameter-still face significant limitations when accessing delicate anatomical structures such as the Fallopian tubes, urethra, and other narrow cavities. In this paper, we introduce an ultracompact endoscope based on the use of a CMOS image sensor from ams OSRAM (NanEyeM) and a single micro-LED (LTW-FC03DCD5). We achieved a total diameter of 1.8 mm, compatible with ultra-narrow cavities of the human body. Optically, a minimal correlated color temperature of 10,343 K and a maximal color rendering index of 73.6 were achieved. These values allow for the detection of structures of small dimensions by morphological and vascular contrast. The optical system demonstrated the ability to resolve up to 83 lp/mm, with a diagonal field-of-view of 115.0° ± 2.4°, measured at different working distances, suitable for working distances encountered in narrow anatomical cavities. This work represents a first prototype for direct visual imaging in human organs not previously accessible by endoscopy, assisting healthcare professionals in clinical assessment and supporting the diagnosis of diseases.