Rectangular Plano-Concave Lens for Compact Imaging
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Solution Overview
Problem
The challenge is to create a small-sized image capturing device with excellent resolving power while minimizing the deterioration in peripheral light amount ratio and aberration correction, as increasing the number of lenses leads to increased height and manufacturing complexity, and existing plano-concave lens configurations with cylindrical profiles result in larger device sizes and inadequate aberration correction.
Innovation Solution
A lens element with an aspheric concave surface on the object side and a substantially rectangular plane surface on the image side, featuring a flange portion or step portion to optimize positioning and support, along with a specific configuration of lenses with positive and negative refractive powers to ensure effective aberration correction and reduced optical total length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the number of lenses is increased to correct aberrations and improve resolving power, then aberration correction and resolving power are improved, but the optical total length increases leading to increased device height
Solution Approach 1:
The patent employs an aspheric surface on the object-side surface of the plano-concave lens to correct aberrations more effectively than traditional spherical surfaces, allowing for better aberration correction with fewer lens elements and reduced optical total length
Solution Approach 2:
The patent optimizes specific parameters including the focal length of the plano-concave lens (set to satisfy -5.0 < f6/f < -2.0 where f is the focal length of the entire imaging lens), the radius of curvature of the concave surface (R6), and the distance between the lens and imaging element (0.005 < d6/f < 0.05) to achieve both compact size and excellent aberration correction
2Manufacturing precision
If the number of lenses is increased to improve resolving power, then resolving power is improved, but manufacturing tolerance factors increase and productivity deteriorates
Solution Approach 1:
The patent combines multiple functions into a single plano-concave lens element: aberration correction through the aspheric concave surface, positioning through the flange portion that fits into a recess, and support through the planar image-side surface. This integration reduces the number of separate components and assembly steps, improving productivity while maintaining excellent aberration correction and resolving power
3Manufacturing precision
If a cylindrical plano-concave lens is used for aberration correction, then aberration correction is achieved, but the device size increases
Solution Approach 1:
The patent uses a plano-concave lens design where the object-side surface is a concave aspheric surface and the image-side surface is a plane, creating an asymmetric structure that corrects aberrations effectively while minimizing the distance to the imaging element and reducing overall device size compared to symmetric cylindrical lens designs
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 production of a small-sized image capturing device with improved resolving power, suppressed peripheral light amount ratio deterioration, and high aberration correction performance, while maintaining high productivity and reducing manufacturing complexities.
Implementation Method 1
a lens element includes an object side surface facing an object side, which is an aspheric surface and a concave surface
Implementation Method 2
an image side surface facing an image surface side, which is substantially plane
Data Source
AI summary
There is provided a lens element which is capable of obtaining a small-sized image capturing device with excellent resolving power, and an image capturing device including the lens element. A shape of an outer profile of an image side surface (L2) is substantially rectangular.