Five-Lens Optical System with Segmented Focus for Compact Devices
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Solution Overview
Problem
Traditional optical systems in devices like mobile phones and tablets face challenges in achieving compact design due to the need for large mechanical back focus and high power focus motors, which hinder miniaturization and slow down focusing speed.
Innovation Solution
An optical system with five lenses, including a movable lens group and a fixed lens group, where the movable group moves along the optical axis for focusing, reducing the burden on the motor and enabling fast focusing with lower power requirements, while maintaining clear imaging quality through balanced refractive power distribution and proper surface design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the entire lens is moved by a focus motor to achieve focusing, then the imaging plane can coincide with the photosensitive surface, but a large mechanical back focus space is required and the device size increases
Solution Approach 1:
The lens is divided into a movable lens group (first four lenses) and a fixed lens group (fifth lens). The movable lens group contains the focusing function and moves along the optical axis, while the fixed lens group remains stationary. This segmentation allows the imaging plane to coincide with the photosensitive surface without requiring large mechanical back focus space, thus reducing device size while maintaining focusing accuracy.
Solution Approach 2:
The patent changes the focusing mechanism from moving the entire lens assembly in one dimension (requiring large back focus space) to moving only a portion of the lens group along the optical axis. This dimensional optimization reduces the space requirement while achieving the same focusing effect.
2Measurement precision
If the entire lens is moved by a focus motor to achieve focusing, then the imaging plane can coincide with the photosensitive surface, but a large power focus motor is required which increases device size
Solution Approach 1:
By segmenting the lens into movable and fixed groups, the mass of the moving object is reduced. The movable lens group (first four lenses) has less mass than the entire lens assembly, requiring a smaller, lower-power focus motor to achieve the same focusing accuracy, thus reducing energy consumption and device size.
3Measurement precision
If the entire lens is moved by a focus motor to achieve focusing, then the imaging plane can coincide with the photosensitive surface, but the focusing speed decreases
Solution Approach 1:
Segmenting the lens into a lighter movable group and a stationary fixed group reduces the mass that needs to be accelerated during focusing. This allows the movable lens group to achieve the required focusing speed faster, improving focusing performance while maintaining imaging accuracy.
4Power
If lens curvature is increased to achieve focusing, then the focusing power is sufficient, but tolerance sensitivity increases and imaging quality deteriorates
Solution Approach 1:
The refractive function is segmented across five lenses with different powers (first lens: negative, second lens: positive, third lens: refractive power, fourth lens: positive and negative, fifth lens: refractive power). This distribution allows each lens to have moderate curvature, reducing tolerance sensitivity and manufacturing difficulty while achieving the required total refractive power for clear imaging.
Solution Approach 2:
Each lens in the system has locally optimized refractive power and surface curvature tailored to its specific position and function. The first lens has negative power to diverge light, the second lens has positive power to converge light, and so on. This local optimization allows the system to achieve high refractive power without any single lens requiring excessive curvature, thereby reducing tolerance sensitivity.
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 system achieves compact design and fast focusing by minimizing lens curvature and aberrations, allowing for smaller device size and improved imaging quality.
Implementation Method 1
The optical system consists of five lenses having refractive power. The five lenses sequentially include a first lens, a second lens, a third lens, a fourth lens, and a fifth lens from an object side to an image side along an optical axis.
Data Source
AI summary
An optical system sequentially includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens. The first lens has negative refractive power. The second lens has positive refractive power. The third lens has refractive power. The fourth lens has positive and negative refractive power. The fifth lens has refractive power. Object side surfaces of the first, second, fourth, and fifth lenses are convex, and image side surfaces of the first, second, fourth, and fifth lenses are concave. An object side surface of the third lens is concave, and an image side surface of the third lens is convex. The first to fourth lenses constitute a movable lens group, and the fourth lens is a fixed lens group. The fixed lens group is fixed relative to an imaging plane, and the movable lens group is movable along the optical axis.