Wide-Angle Endoscope Lens Focal Adjustment
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Solution Overview
Problem
Conventional endoscopes with wide-angle optical systems face challenges in maintaining focus due to the narrow depth of field when using high-resolution image sensors, necessitating a method for adjusting the focal position while minimizing the size and weight of the optical system.
Innovation Solution
A wide-angle optical system with a lens component comprising multiple optical surfaces, including a first lens unit with negative refractive power, a second lens unit with positive refractive power, and a third lens unit with positive refractive power, where the second lens unit is moved to adjust the focal position, ensuring a compact design and low light-ray height, thereby allowing for effective focal adjustment without increasing the optical system's diameter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of pixels in the image sensor is increased to improve resolution, then the image quality is improved, but the depth of field becomes narrower making it difficult to observe the required observation depth
Solution Approach 1:
The patent implements a variable focus optical system where the third lens unit can be moved along the optical axis to adjust the focal position. This dynamic adjustment allows the system to adapt the depth of field to match the required observation depth, resolving the contradiction between high resolution and adequate depth of field.
2Adaptability or versatility
If an actuator is provided around the optical system to enable inner focusing, then the focal position can be adjusted, but the size and weight of the optical system increase
Solution Approach 1:
The patent extracts the focusing function from a separate actuator mechanism and integrates it directly into the optical system by making the third lens unit movable. This eliminates the need for additional actuators and mounting structures, thereby reducing the overall weight and size of the optical system while maintaining focal position adjustment capability.
3Adaptability or versatility
If the angle of view is increased to 140 degrees or more for wide-angle observation, then the observation range is improved, but the optical system requires larger size and higher actuator output
Solution Approach 1:
The patent divides the optical system into multiple lens units with specific refractive powers. The third lens unit with positive refractive power is specifically designed to correct optical aberrations introduced by the wide-angle configuration, allowing the system to achieve a large angle of view while maintaining compact size and reducing actuator requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables a wide-angle optical system with a large angle of view and improved resolution, capable of maintaining sharp images even with high-pixel image sensors, while keeping the optical system compact and lightweight, thus addressing the challenge of focal adjustment in endoscopes.
Implementation Method 1
a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, and a third lens unit having a positive refractive power
Data Source
AI summary
A wide-angle optical system is a wide-angle optical system having a lens component, and includes in order from an object side, a first lens unit having a negative refractive power, a second lens unit having a negative refractive power, and a third lens unit having a positive refractive power. At the time of carrying out a focal-position adjustment from a far point to a near point, the second lens unit is moved from a first position toward a second position. The third lens unit includes not less than three lens components. Not less than three lens components include a first lens component and a second lens component. Each of the first lens component and the second lens component has a positive refractive power, and following conditional expression (1) is satisfied:0.8<f3L12/fL<6.0 (1).