Variable-Power Optical System Using Plastic Lenses
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Solution Overview
Problem
Conventional variable-power optical systems for mobile devices face challenges in achieving compact size and low cost while supporting high-pixel image pickup elements, often requiring increased lens numbers, weight, and cost due to the use of glass lenses, which also complicates production and adjustment.
Innovation Solution
A variable-power optical system with a negative-lead configuration, comprising a first lens group with two or more plastic lenses, a second lens group with positive optical power, and a third lens group, optimized by specific focal length and image-forming magnification ratios to reduce overall length and weight, and correct chromatic aberrations, using conditional expressions to ensure adequate optical power distribution and minimize manufacturing errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If glass lenses are used in conventional variable-power optical systems, then optical performance is improved, but weight and cost increase significantly
Solution Approach 1:
The patent changes the material parameter from glass to plastic lenses, specifically using injection-molded plastic lenses with optimized refractive indices and Abbe numbers to achieve the required optical performance while dramatically reducing weight and cost
Solution Approach 2:
The patent employs inexpensive plastic lenses that can be mass-produced through injection molding, replacing expensive glass lenses. These plastic lenses achieve sufficient optical performance for mobile device applications at a fraction of the cost and weight of glass alternatives
2Reliability
If glass lenses are used in conventional variable-power optical systems, then optical performance is improved, but production complexity and cost increase
Solution Approach 1:
The patent replaces the traditional glass lens manufacturing and assembly process with injection-molded plastic lenses that are formed directly in their final shape, eliminating the need for complex grinding, polishing, and coating processes associated with glass lenses
Solution Approach 2:
The patent utilizes the molding process to directly create lenses with precise optical parameters, replacing the mechanical processing required for glass lenses. This enables mass production with consistent optical quality and reduced manufacturing steps
3Reliability
If more lenses are added to achieve compact configuration, then optical performance is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple lens functions into fewer plastic lens elements, using aspheric surfaces and optimized material properties to achieve the optical performance of multiple spherical glass lenses with fewer plastic components
Solution Approach 2:
The patent employs aspheric plastic lenses where the surface shape parameter varies continuously, allowing a single lens element to correct multiple aberrations that would traditionally require multiple separate spherical lens elements
4Reliability
If lens traveling distance is increased to achieve variable power, then optical performance is improved, but overall optical length increases
Solution Approach 1:
The patent uses plastic lenses with higher refractive indices and optimized Abbe numbers compared to traditional glass lenses, allowing for shorter focal lengths and reduced optical path lengths while maintaining the required variable power range and optical performance
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 results in a compact, low-cost variable-power optical system that effectively corrects aberrations and reduces the load on the lens drive apparatus, enabling high-pixel image capture without significant increases in weight or production complexity.
Implementation Method 1
a first lens group with a negative optical power
Implementation Method 2
a second lens group with a positive optical power, moving when a power of the variable-power optical system varies
Implementation Method 3
a third lens group with a positive or negative optical power
Implementation Method 4
the first lens group comprises two or more lenses including one positive lens and one negative lens which include at least two or more lenses made of a plastic material
Data Source
AI summary
A variable-power optical system includes, in order from an object side thereof: a first lens group with a negative optical power; a second lens group with a positive optical power, moving when the power of the variable-power optical system varies; and a third lens group with a positive or negative optical power. The first lens group includes two or more lenses including one positive lens and one negative lens which include at least two or more lenses made of a plastic material. The variable-power optical system satisfies the predetermined conditional expressions relating to is a focal length of the first lens, a focal length of the second lens, a composite focal length of the total optical system, and an image-forming magnification of the second lens group at a telephoto end.