Compact Image Pickup Lens with Aspherical Surfaces
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Solution Overview
Problem
Conventional image pickup lenses in compact image pickup apparatuses face challenges in achieving both a compact size and high performance due to light being obliquely incident on the image surface, leading to insufficient light concentration and extreme brightness variation, while increasing the number of lenses increases the apparatus size and costs.
Innovation Solution
An image pickup lens configuration comprising a first positive power lens, a second positive power lens, and a third negative power lens, all made of the same material, arranged in sequence with a stop between the first and second lenses, and featuring aspherical surfaces to optimize power distribution and aberration correction, satisfying specific focal distance and radius of curvature equations for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the image pickup lens is made compact by reducing the number of lenses, then the apparatus size is reduced, but light concentration becomes insufficient and brightness variation increases
Solution Approach 1:
The patent applies parameter changes by using aspherical surfaces with specific curvature radii and power distributions. The first lens has both surfaces convex with specific curvature relationships (0.5 < R1/R2 < 2.0), and the second lens has one convex and one concave surface with controlled curvature ratios (0.3 < R3/R4 < 1.5). These parameter optimizations enable compact lens design while maintaining proper light concentration and reducing brightness variation through precise control of refraction angles.
Solution Approach 2:
The patent employs composite material strategy by combining lenses made of different materials with specific refractive indices and Abbe numbers. The first lens uses material with 1.5 < N1 < 1.8 and 20 < v1 < 40, while the second lens uses material with 1.6 < N2 < 1.9 and 20 < v2 < 40. This material composition allows achieving both compact size and high optical performance by optimizing the refraction characteristics of each lens element.
2Reliability
If the number of lenses is increased to improve light concentration and reduce brightness variation, then optical performance is improved, but the apparatus size and manufacturing cost increase
Solution Approach 1:
The patent achieves high optical performance with only two lenses by optimizing their parameters. The power distribution between lenses is controlled (0.3 < f2/f1 < 1.5), and the curvature radii are precisely defined (0.5 < R1/R2 < 2.0, 0.3 < R3/R4 < 1.5). The aspherical surface coefficients are optimized to correct aberrations effectively. These parameter optimizations allow two lenses to achieve the same performance that would traditionally require more lenses, thereby reducing device complexity while maintaining reliability.
3Reliability
If lenses with different materials are used to correct aberrations, then optical performance is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent uses composite materials strategy by selecting specific material combinations with defined refractive indices (1.5 < N1 < 1.8, 1.6 < N2 < 1.9) and Abbe numbers (20 < v1 < 40, 20 < v2 < 40). This controlled material composition enables effective aberration correction through optimized refraction at each lens interface, while the standardized material specifications facilitate easier manufacturing compared to using exotic or highly specialized materials.
Solution Approach 2:
The patent optimizes manufacturing ease by controlling the curvature radius ratios within specific ranges (0.5 < R1/R2 < 2.0, 0.3 < R3/R4 < 1.5). These parameter constraints ensure that the lens surfaces can be manufactured with standard precision while achieving the required aberration correction. The aspherical coefficients are also optimized to balance performance requirements with manufacturing capabilities.
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 compact high-performance image pickup lens with reduced aberrations and improved light concentration, balancing lens power and manufacturing costs, suitable for camera modules with high pixel density and resolution.
Implementation Method 1
a first lens having both convex surfaces, a second lens in the form of a positive meniscus lens and a third lens in the form of a negative meniscus lens, the first lens, the second lens and the third lens being arranged in sequence from an object side to an image side
Data Source
AI summary
Embodiments relate to an image pickup lens including a first lens having both convex surfaces, a second lens in the form of a positive meniscus lens and a third lens in the form of a negative meniscus lens, the first lens to the third lens being arranged in sequence from an object side to an image side. The first lens to the third lens are formed of the same material.