

Minimally Invasive Surgery (MIS) has become the mainstream of modern surgical treatment with its advantages of small incisions, fast recovery and low trauma. The core of MIS is the medical endoscope—and the endoscope probe’s “eye” is the ultra-miniature optical lens assembly.
Medical endoscope micro lenses need to achieve high-definition, distortion-free imaging in a space of only a few millimeters, while meeting strict medical standards such as biocompatibility and sterilization resistance. As a professional optical lens supplier with rich experience in miniaturized lens R&D and production, TOWIN has launched a series of low-distortion micro lenses for MIS endoscopes. These lenses feature small mount sizes, ultra-compact TTL (Total Track Length) and IR compatibility, perfectly matching the design requirements of various endoscope probes (gastroscope, laparoscope, rhinoscope, etc.).
Medical endoscope micro lenses are ultra-miniature optical lens assemblies designed for endoscope probes. They collect and transmit optical signals from the surgical site, convert them into real-time visual images through the camera sensor, and help surgeons complete precise operations in tiny spaces. The core design principles are miniaturization, low distortion and high light transmittance.
TOWIN classifies medical endoscope micro lenses according to four core application dimensions, covering all MIS endoscope design needs:
The performance of medical endoscope micro lenses directly determines the imaging quality of the endoscope and the safety of MIS. Below are the core technical parameters and their practical significance in surgery, with TOWIN’s product design standards as the reference:
| Parameter | Definition | Core Requirement for MIS | TOWIN Product Standard |
| Focal Length | The distance from the lens center to the imaging surface | Ultra-short focal length (adapts to miniaturized probes) | 0.65mm – 2.4mm |
| FOV (Field of View) | The range of the surgical site that the lens can capture | Wide/ultra-wide angle (reduces probe movement, avoids tissue damage) | 71° – 115° (diagonal) |
| TV Distortion | The degree of image deformation caused by the lens | Ultra-low distortion (avoids misjudgment of lesion size/position) | <1% / <1.5% / <4.3% |
| Resolution | The ability of the lens to distinguish fine details | Matching sensor pixel (0.3MP-5MP for MIS) | 0.3MP/1MP/5MP |
| Aperture (FNo.) | The light transmittance of the lens | Fixed large aperture (ensures clear imaging in low-light surgical environments) | F2.0 / F2.2 / F2.4 |
| Mount Size | The thread specification of the lens connection probe | Small/ultra-small mount (adapts to thin probe design) | M2.6/M3.5/M4/M5 |
| TTL | Total length of the lens (ultra-compact is critical) | Ultra-short TTL (fits limited probe internal space) | 1.78mm – 4.18mm |
| CRA (Chief Ray Angle) | The angle of the main light ray entering the sensor | Low CRA (reduces image vignetting, improves edge clarity) | ≤30° / <34.1° / ≤35° |
| R.I. (Light Transmittance) | The ratio of light transmitted through the lens | High transmittance (ensures bright imaging) | ≥33% / >36% / ≥43% |
Core Performance Highlight: TOWIN’s medical endoscope micro lenses achieve TV distortion <1% for most models, which is the strictest standard for medical imaging lenses, completely avoiding image deformation in surgical observation.
TOWIN’s low-distortion micro lenses cover all mainstream MIS departments, with different specifications matching the unique design needs of various endoscopes. Each scenario is equipped with customized lens parameters to ensure optimal imaging:
Medical endoscope micro lenses are high-precision optical assemblies, and each component is designed for medical-grade performance and miniaturization. TOWIN’s lenses adopt a modular design, with 5 core components and clear division of labor:
Medical endoscope micro lenses are in contact with human tissues/body fluids (or close to the surgical site), so materials must meet three core requirements: biocompatibility, sterilization resistance and mechanical strength. TOWIN’s material selection for medical-grade lenses is strictly in accordance with medical standards:
All TOWIN medical endoscope micro lenses comply with the ISO 10993 international medical device biocompatibility standard (the core standard for medical materials). The key test items are as follows:
| ISO 10993 Test Item | Test Requirement | TOWIN Compliance Standard |
| Cytotoxicity | No cell death/abnormal proliferation | Grade 0 (no cytotoxicity) |
| Skin Irritation | No redness, swelling or rash on the skin | No irritation (Grade 0) |
| Sensitization | No allergic reaction in the human body | Non-sensitizing (Grade 0) |
| Hemolysis Test | Red blood cell rupture rate <5% | Hemolysis rate <2% |
Sterilization Resistance: TOWIN’s medical micro lenses support all mainstream medical sterilization methods for repeated use (≥100 times):
As a professional optical lens supplier with rich experience in miniaturized lens R&D, TOWIN has launched a series of low-distortion micro lenses for MIS endoscopes, covering M2.6-M5 mounts, 0.65mm-2.4mm focal lengths and 71°-115° FOV. All lenses adopt ultra-compact design and medical-grade materials, perfectly matching the design needs of various endoscope probes.
TOWIN Medical Endoscope Micro Lens Full Specification Table
| Model No. | Focal Length | Diagonal FOV | Resolution | TV Distortion | Aperture | Mount | TTL (mm) | Optical Structure | Core Highlight |
| M201319007020F | 1.3mm | 77° | 1MP | <1% | F2.0 | M2.6×0.1 | 1.78 | 3P+IRCF | Ultra-small mount, IR built-in, 1.78mm ultra-short TTL |
| M402315006522R | 2.3mm | 77° | 5MP | <1.5% | F2.2 | M5×0.25 | 4.18 | 3P | 5MP high resolution, M5 standard mount, for laparoscope |
| M401916006520 | 1.9mm | 78° | 0.3MP | <1% | F2.0 | M4×0.25 | 3.3 | 3P | 78° wide angle, F2.0 large aperture, low-light imaging |
| M300611108824F | 0.65mm | 115° | QVGA/VGA | <4.2% | F2.4 | M3.5×0.2 | 3 | 3P+IR | 115° ultra-wide angle, 0.65mm ultra-short focal length, for gastroscope |
| M502415006022F | 2.4mm | 71° | 5MP | <1% | F2.2 | M5×0.35 | 3.3 | 3P+IRCF | 5MP HD, <1% ultra-low distortion, IR built-in, ≤30° low CRA |
Q1: What are the key factors to consider when selecting medical endoscope micro lenses for MIS?
A: The core selection factors are matching the endoscope probe size (mount/TTL), adapting to the surgical scenario (FOV/resolution), and meeting medical standards (biocompatibility/sterilization resistance). TOWIN’s sales team will provide one-to-one matching solutions according to your probe design parameters.
Q2: Why is low TV distortion the most important performance index for medical endoscope micro lenses?
A: In MIS, surgeons judge the size, position and shape of lesions through endoscope images. If the lens has high distortion, the lesion image will be deformed, leading to surgical misjudgment (e.g., overestimation/underestimation of tumor size). TOWIN’s <1% ultra-low distortion completely avoids this problem.
Q3: Can TOWIN customize medical endoscope micro lenses for non-standard endoscope probe designs?
A: Yes. TOWIN provides OEM/ODM full customization service for medical endoscope micro lenses, including:
Q4: What is the delivery time of TOWIN’s standard and customized medical endoscope micro lenses?
A: Standard models: In stock, delivery time is 3-5 working days; Custom models: According to the customization difficulty, the delivery time is 15-30 working days (including sample testing and mass production).
Minimally invasive surgery is the inevitable trend of modern medical development, and the miniaturization and high-definition of endoscopes are the core direction of technological upgrading—while the key to this upgrade is the medical endoscope micro lens.
TOWIN, as a professional optical lens supplier, has focused on the R&D and production of low-distortion miniaturized lenses for many years. Our medical endoscope micro lens series has the advantages of small mount, ultra-compact TTL, low distortion and IR compatibility, and all products comply with ISO 10993 biocompatibility standards. The full range of specifications covers all mainstream MIS scenarios, and OEM/ODM customization is supported to meet personalized endoscope probe design needs.
TOWIN adheres to the concept of PROFESSIONAL-ALL-EASY-FAST, and provides one-stop optical solutions from lens selection, customization to mass production for global medical device manufacturers. If you have any needs for medical endoscope micro lenses, please contact us at info@towin-elec.com—our professional optical engineers will provide you with the most suitable solution!
TOWIN Optics: Your reliable partner for medical endoscope micro lenses!