Three-Lens Resin Optical System for Wide-Angle Compact Imaging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Optical apparatuses such as endoscopes face challenges in achieving a wide angle of view while maintaining a short overall length and reducing costs, as excessive reduction in the number of lenses leads to inadequate aberration correction, and using low-cost resin lenses with small refractive indices complicates widening the angle of view and miniaturization.
Innovation Solution
An image pickup apparatus with an optical system comprising a first lens with negative refractive power, a second lens with positive refractive power, an aperture stop, and a third lens, all made from materials with refractive indices not higher than 1.70, satisfying specific conditional expressions to achieve a wide angle of view and small size while correcting various aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the number of lenses is reduced to lower cost, then manufacturing cost is reduced, but aberration correction becomes inadequate
Solution Approach 1:
The patent applies parameter changes by utilizing resin materials with specific refractive index ranges (1.40 ≤ nd < 1.70) and controlling the optical system configuration (focal length, lens spacing) to achieve adequate aberration correction with only three lenses, thereby resolving the contradiction between reduced lens count and maintained optical performance
Solution Approach 2:
The patent employs composite material strategy by using resin materials instead of traditional glass lenses, combining cost advantages of resin with optimized optical properties through selection of materials having specific refractive index characteristics, enabling both cost reduction and sufficient aberration correction
2Ease of manufacture
If resin materials with small refractive indices are used to reduce cost, then manufacturing cost is reduced, but widening angle of view and miniaturization become more difficult
Solution Approach 1:
The patent resolves this contradiction by establishing specific parameter ranges for the optical system, including the conditional expressions for focal length ratios and lens spacing, which enable wide angle of view (130 degrees or more) and compact size even when using resin materials with refractive indices in the range of 1.40 ≤ nd < 1.70
3Length of moving object
If the overall length of the optical system is shortened to improve operability, then device length is reduced, but achieving wide angle of view with adequate aberration correction becomes more difficult
Solution Approach 1:
The patent applies parameter changes by optimizing the optical system configuration with specific focal length ratios (0.30 ≤ |f1/FL| < 0.50, 0.80 ≤ f2/FL < 1.20) and controlling the total track length through the conditional expression 2.0 ≤ Σd/FL < 5.5, achieving both compact size and adequate aberration correction
Solution Approach 2:
The patent utilizes aspheric surfaces on lens elements to correct aberrations in a different dimensional approach, allowing compact optical system design while maintaining adequate aberration correction performance through surface geometry optimization rather than relying solely on increased system length
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 the capture of a wide-angle optical image with high resolution and effective aberration correction while maintaining a compact size, suitable for applications like endoscopes and car-mounted cameras.
Implementation Method 1
an optical system which includes a plurality of lenses
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, a second lens having a positive refractive power, an aperture stop, and a third lens, 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) and (2) are satisfied:2.0<Σd/FL<5.5 (1), and0.5<Φ1L/IH<3.0 (2).