Bonded Lens Group for Compact Optical Systems
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Solution Overview
Problem
Conventional subminiature optical systems for vehicles face challenges in achieving high resolution while maintaining a compact design, leading to increased length and susceptibility to scattered reflection and chromatic aberration, especially when transitioning between day and night photography.
Innovation Solution
A subminiature optical system is designed with a second lens group formed by bonding two lenses with different refractive variances, positioned close to an aperture stop, to minimize refractive index changes and reduce axial chromatic aberration, thereby improving yield and focus consistency across different lighting conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the second lens is divided into two sheets of lenses spaced apart to improve resolution, then resolution is improved, but the optical system length increases and scattered reflection and chromatic aberration increase
Solution Approach 1:
The patent merges two separate lens sheets into a single bonded lens unit, eliminating the air gap between them. This reduces the optical system length while maintaining the resolution benefits of having two lens elements with different refractive powers.
Solution Approach 2:
The patent uses a bonded lens structure where two lens materials with different refractive indices are optically bonded together. This composite lens structure corrects chromatic aberration and reduces scattered reflection while maintaining compact dimensions.
2Length of stationary object
If the interval between the second and third lenses is narrowed to reduce optical system length, then optical system length is reduced, but scattered reflection increases and chromatic aberration increases
Solution Approach 1:
The bonded lens combines two lens materials with different refractive indices in direct contact, eliminating air-glass interfaces that cause scattered reflection. The composite structure also provides chromatic aberration correction through the differential refraction of the two materials.
Solution Approach 2:
The patent changes the refractive index parameter distribution by using two different lens materials with specific refractive powers (+1.7 or more and -1.7 or more). This parameter optimization reduces chromatic aberration while maintaining a narrow lens interval.
3Ease of manufacture
If three sheets of lenses are used in a triplet structure for bright optical performance, then ease of manufacture and cost are improved, but resolution remains low
Solution Approach 1:
The patent merges two lens sheets into a bonded lens unit, effectively creating a four-element optical system in a compact form. This maintains the ease of manufacture advantage while achieving superior resolution compared to traditional triplet structures.
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 enhances image resolution, reduces focus differences between day and night images, and minimizes scattered reflections, improving the overall optical system's performance and assembly efficiency.
Implementation Method 1
the second lens group is configured of a plurality of lenses of which facing surfaces are bonded to each other... two lenses having different variance values are bonded to each other and the bonded lens is disposed closely to an aperture stop to reduce axial chromatic aberration
Data Source
AI summary
Disclosed herein is a subminiature optical system including: a first lens group having positive refractive power; a second lens group having negative refractive power; and a third lens group having positive refractive power, wherein the second lens group is configured of a plurality of lenses of which facing surfaces are bonded to each other and the following Conditional Equation is satisfied:n1, n3>1.7 [Conditional Equation].