Application and Core Parameter Precision of Optical Rod Lenses in Medical Industry
Optical rod lenses are cylindrical precision optical elements, mostly made of optical glass or fused silica. With precisely ground and polished end faces and cylindrical surfaces, they feature straight light transmission, low distortion and high transmittance. As the core component of rigid medical endoscope imaging systems, they are widely used in minimally invasive diagnosis and treatment equipment.
1. Applications of Optical Rod Lenses in Medical Field
1、Rigid Endoscopes (Laparoscope, ENT endoscope, Arthroscope)
The imaging core inside medical rigid endoscopes consists of multiple sets of cascaded optical rod lenses. Rod lenses can stably transmit images inside slender tube bodies and realize high-definition imaging within narrow human cavities. They support laparoscopic minimally invasive surgery, ENT examination and joint cavity exploration to help doctors observe lesions. Featuring compact structure, rod lenses fit small-diameter tubes to meet the demand of tiny minimally invasive wounds.
2、Medical Optical Inspection & Observation Equipment
For surgical viewing scopes and intracavity inspection devices, optical rod lenses build relay optical paths to transmit clear, distortion-free images. Compared with ordinary lenses, rod lenses maintain image quality over long distances in narrow spaces, suitable for outpatient examinations and real-time intraoperative observation.
3、Optical Components for Laser Diagnosis & Treatment
Some laser medical devices adopt rod lenses as light-guiding elements to transmit laser beams evenly for laser ablation, tissue physiotherapy and other medical operations. It ensures uniform and stable light spots and improves the controllability of diagnosis and treatment.
2. Core Technical Parameters of Optical Rod Lenses
1、Material: K9 optical glass, fused silica. Visible-light or UV compatible materials optional according to wavelength.
2、Diameter: Medical common range Φ1mm ~ Φ10mm. Micro small-diameter rod lenses customizable for ultra-thin endoscopes.
3、Length: 5mm ~ 200mm, custom length according to endoscope optical path design.
4、Refractive index: Determined by glass type, generally from 1.45 to 1.52.
5、Coating: Anti-reflection (AR) coating on end faces to reduce reflection loss and raise transmittance. Some versions support waterproof & antifouling coating to adapt to body fluid environment.
3. Machining Precision Requirements for Medical Rod Lenses
1、End face flatness: λ/4 ~ λ/10 @632.8nm to guarantee wavefront quality.
2、End face parallelism: ≤30 arcseconds, preventing image shift when multiple rod lenses are cascaded.
3、Cylindrical surface roughness: Ra ≤0.01μm to reduce stray light.
4、Diameter tolerance: ±0.005mm, ensuring smooth assembly into endoscope tubes.
5、Chamfer: Precision edge chamfer to avoid chipping during assembly and prevent scratch on human tissue.
6、Angle tolerance: Perpendicularity between end face and cylinder ≤1 arcminute to avoid optical path deflection.
4. Summary
Optical rod lenses are core optical elements for rigid endoscopes. Relying on high-precision cylinder and end-face machining, they realize relay imaging in minimally invasive medical equipment. Strict control of dimension, surface profile and angle precision guarantees image clarity and safety of medical devices. With continuous development of minimally invasive medical technology, demands for smaller diameter and higher surface precision rod lenses will keep growing.
