Five-Lens Imaging System Telecentricity and Aberration Control
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Solution Overview
Problem
Existing imaging lenses with a large number of pixels face challenges in maintaining telecentric property and manufacturing sensitivity, particularly due to high dispersion and chromatic aberration issues, which are exacerbated by concave surfaces in lenses.
Innovation Solution
An imaging lens system comprising five lenses with specific refractive powers and surface shapes, including a positive first lens, a negative meniscus second lens, a positive meniscus third lens, an aspheric fourth lens, and an aspheric fifth lens, optimized to satisfy conditional expressions for Abbe numbers and thickness ratios, ensuring telecentricity and reduced manufacturing sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the surface of the second lens on the object side is made concave to ensure telecentric property, then the telecentric property is improved, but the manufacturing sensitivity becomes high and image surface variation easily occurs
Solution Approach 1:
The patent inverts the conventional design by making the second lens a positive meniscus lens with the convex surface facing the object side, rather than the traditional concave surface configuration. This inversion maintains the telecentric property while significantly reducing manufacturing sensitivity and image surface variation.
2Reliability
If the number of lenses is increased to be compatible with a larger number of pixels, then the performance is improved, but the device complexity increases
Solution Approach 1:
The patent changes key parameters including the refractive powers, Abbe numbers, and surface curvatures of the five lenses to achieve optimal performance for high-pixel imaging devices. By carefully selecting and optimizing these parameters, the patent provides an effective solution for high-performance imaging while maintaining a manageable five-lens configuration.
3Reliability
If the aperture diaphragm is placed close to the object side to ensure telecentric property, then the telecentric property is improved, but the manufacturing sensitivity becomes high
Solution Approach 1:
The patent applies local quality by optimizing the specific configuration of the second lens (positive meniscus with convex surface to object side) to compensate for the manufacturing sensitivity issues that would otherwise result from placing the aperture diaphragm close to the object side. This localized optimization maintains telecentric property while reducing overall manufacturing sensitivity.
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 five-lens system effectively corrects axial chromatic aberration and lateral color, enhances manufacturing suitability, and ensures telecentricity, while allowing for miniaturization and improved performance with a larger number of pixels.
Implementation Method 1
a first lens of a positive lens with a convex surface directed to the object side; a second lens having a negative refractive power and a meniscus shape; a third lens having a positive refractive power and a meniscus shape; a fourth lens with both surfaces being an aspheric surface; and a fifth lens of a positive or negative lens with both surfaces being an aspheric surface
Data Source
AI summary
An imaging lens is provided and includes: a positive first lens with a convex surface directed to the object side; a second lens having a negative meniscus shape with a concave surface directed to the image side; a third lens having a positive meniscus shape with a convex surface directed to the image side; a negative fourth lens with both surfaces being an aspheric surface and the image-side surface being concave in the proximity of the optical axis; and a positive or negative fifth lens with both surfaces being an aspheric surface, in order from the object side. The following conditional expressions are satisfied as for Abbe numbers vd1 and vd2of the first lens and the second lens and Abbe number vd4 of the fourth lens.vd1>50 (1)vd2<30 (2)vd4<30 (3)