In medical endoscope equipment, the optical parameters of camera modules directly determine the accuracy of clinical observation and operational efficiency, with the matching of focal length and field of view (FOV) being core design elements. These two parameters are not isolated—with a fixed sensor size, a shorter focal length results in a larger FOV and a wider observation range, while a longer focal length leads to a smaller FOV and stronger detail magnification capability. Different combinations target distinct clinical scenarios with unique advantages. The 1MP high-definition miniature medical endoscope camera module based on OmniVision's OV9734 sensor (focal length 1.25mm + FOV 90°) exemplifies precise optical parameter matching, making it an ideal design for multi-scenario clinical needs.
Short Focal Length + Large FOV: Clinical Value of Wide Coverage and Rapid Localization
Taking the module’s 1.25mm short focal length paired with a 90° horizontal field of view (DFOV) as an example, its core advantage lies in achieving wide coverage in narrow spaces—a feature critical for scenarios requiring rapid target localization or overall structural observation.
From an optical perspective, the 1.25mm short focal length allows the lens to capture a broader range of images at close distances (within the 10-100mm focusing range), while the 90° FOV covers most areas of human cavities or surgical fields. In laparoscopic surgery, this combination enables doctors to observe the overall shape of organs and their relationship with surrounding tissues with a single lens positioning, reducing frequent lens movement that disturbs the abdominal environment and lowers the risk of tissue damage. In otolaryngology examinations, the short focal length combined with a large FOV can fully cover the entire nasal and ear canals in one view, quickly identifying foreign bodies or lesions to improve examination efficiency.
The module’s design further enhances this advantage: its 3.6mm slim lens diameter ensures smooth access to narrow cavities even during wide-field observation. Meanwhile, the combination of F4.0 aperture and 1.4μmx1.4μm pixel size optimizes light sensitivity and supplements illumination (via 4 integrated LED beads), compensating for potential light loss from the short focal length and ensuring clear wide-field imaging. Additionally, distortion is controlled below -20%, avoiding image deformation common in large FOV designs and providing doctors with accurate spatial judgment references.
Medium Focal Length + Medium FOV: Universal Adaptation for Balancing Range and Detail
When the focal length extends to 2-3mm and the FOV narrows to 60-80°, the "medium focal length + medium FOV" combination offers a balance between observation range and detail presentation, suitable for scenarios requiring both overall structural awareness and local feature analysis.
This configuration maintains a reasonable observation breadth (e.g., tracking intestinal pathways during gastroenteroscopy) while providing moderate magnification through the longer focal length, clearly revealing subtle mucosal protrusions，congestion, and other details. In gastroscopy, for instance, the medium FOV avoids edge distortion from overly wide angles, while the focal length design allows doctors to seamlessly switch between observing the stomach’s overall morphology and focusing on suspicious lesion textures without frequent focus adjustments.
Flexibility in focusing range is crucial for such combinations. Similar to this module’s 10-100mm wide focusing range, the medium focal length enables smooth transitions within this interval, meeting both mid-distance cavity observation needs and close-up (within 10mm) detailed inspection via manual focusing, thus providing multi-dimensional clinical diagnostic information.
Long Focal Length + Small FOV: Specialized Adaptation for High-Precision Detail Observation
When the focal length further extends beyond 4mm and the FOV shrinks below 60°, the "long focal length + small FOV" combination becomes a specialized choice for high-precision detail observation and delicate operations, particularly in scenarios demanding microscopic structural clarity.
The high magnification from the long focal length clearly visualizes tiny structures such as nerve fibers, microvessels, and subtle mucosal lesions. In neuroendoscopic surgery, this combination helps doctors accurately identify the relationship between skull base nerves and surrounding blood vessels to avoid accidental damage. In gynecological hysteroscopy, it can magnify endometrial gland openings, improving the detection rate of early lesions.
Notably, such configurations impose strict requirements on lens stability and manufacturing processes. Similar to this module’s use of SMT (Surface Mount Technology) and AA (Active Alignment) processes, optical alignment errors in long focal length designs are easily amplified. Active alignment technology ensures precise matching between the lens and sensor, preventing image shifts or blurring and providing a stable optical foundation for high-precision observation.
Conclusion: "Customized" Optical Logic Based on Clinical Scenarios
The matching of focal length and FOV in medical endoscope camera modules essentially "translates" clinical needs into optical parameters: short focal length + large FOV serves rapid localization and wide observation; medium combinations balance range and detail; long focal length + small FOV focuses on high-precision operations. This OV9734-based module, with its precise 1.25mm focal length and 90° FOV ratio, demonstrates significant advantages in wide-field observation within narrow spaces. Its wide focusing range, low distortion control, and reliable manufacturing processes further enable the clinical value of "broad coverage, true imaging, and flexible operation" in practical applications.
As medical technology advances toward minimally invasive and precision-oriented development, the scientific matching of focal length and FOV will remain central to endoscope module design, providing more scenario-adapted optical solutions for diverse clinical needs.
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