Resin Lens Optical System for Wide-Angle Aberration Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image pickup apparatuses face challenges in achieving a wide angle of view and small size while maintaining optical performance, particularly in applications like endoscopes and digital cameras, due to limitations in refractive index and material costs, especially with resin lenses which have lower refractive indices.
Innovation Solution
An optical system comprising a plurality of lenses with specific refractive powers and configurations, including a first lens with negative refractive power, an aperture stop, and a second and third lens with positive refractive power, all made from materials with refractive indices not exceeding 1.70, optimized by conditional expressions to correct aberrations and maintain performance across temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If resin material is used for lenses to reduce cost, then manufacturing cost is reduced, but refractive index decreases making it difficult to achieve wide angle of view and small size
Solution Approach 1:
The patent changes the refractive index parameter by using resin materials with refractive index of 1.70 or less, specifically optimizing the balance between cost and optical performance. This parameter change allows achieving wide angle of view (90 degrees or more) while maintaining small size and low cost through precise control of refractive index rather than using high refractive index glass materials.
2Ease of manufacture
If resin material with low refractive index is used, then manufacturing cost is reduced, but angle of view cannot be widened effectively
Solution Approach 1:
The patent optimizes the refractive index parameter to 1.70 or less, which is a specific parameter change that enables achieving both cost reduction and wide angle of view. This precise parameter control allows the optical system to achieve 90 degrees or more angle of view while using cost-effective resin materials.
Solution Approach 2:
The patent uses composite lens structures with multiple resin lenses (first lens with negative refractive power, second lens with positive refractive power, and third lens with positive refractive power). This composite approach allows achieving wide angle of view and effective aberration correction using resin materials with refractive index of 1.70 or less, combining the advantages of multiple materials with different optical properties.
3Reliability
If glass material with high refractive index is used, then optical performance is improved, but manufacturing cost increases
Solution Approach 1:
The patent changes the material parameter from high refractive index glass to resin with refractive index of 1.70 or less. This parameter change maintains effective optical performance (aberration correction and wide angle of view) while significantly reducing manufacturing cost, as resin materials are more cost-effective than glass materials.
Solution Approach 2:
The patent adopts resin materials which are cheaper and more easily manufacturable compared to glass materials. Although resin may have different durability characteristics, the patent prioritizes cost-effectiveness and manufacturability, using resin lenses that can be easily molded and produced at lower cost while achieving the required optical performance.
4Ease of manufacture
If number of lenses is reduced to lower cost, then manufacturing cost is reduced, but optical performance and aberration correction deteriorate
Solution Approach 1:
The patent uses a composite structure of three resin lenses with specific refractive powers (first lens: negative, second lens: positive, third lens: positive). This composite approach achieves effective aberration correction and wide angle of view while using cost-effective resin materials, balancing the number of lenses with optical performance requirements.
Solution Approach 2:
The patent assigns different refractive powers and positions to each lens (first lens with negative power at object side, second and third lenses with positive power toward image side). This local differentiation of optical properties within the lens group enables effective aberration correction while maintaining a relatively simple structure with only three lenses, achieving both cost reduction and performance maintenance.
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 small-sized, lightweight image pickup apparatus with a wide angle of view and effective aberration correction, achieving high-resolution images while being cost-effective and adaptable to temperature fluctuations.
Implementation Method 1
an optical system which includes a plurality of lenses... a first lens having a negative refractive power... a second lens having a positive refractive power... a third lens having a positive refractive power
Data Source
AI summary
An image pickup apparatus includes an optical system which includes a plurality of lenses, and an image sensor which is disposed at an image position of the optical system, wherein the optical system includes in order from an object side, a first lens having a negative refractive power, an aperture stop, a second lens having a positive refractive power, and a third lens having a positive refractive power, and each of the first lens, the second lens, and the third lens is formed of a material having a refractive index not higher than 1.70, and the following conditional expressions (1), (2), (3), and (4) are satisfied:0<f3/f2≤1.7 (1),0.5<Φ1L/IH<3.0 (2),0.05<D1R2L/Σd<0.5 (3), and−0.4<f1/R1L<0.2 (4).