Single-Focus Lens System with Aspheric Cemented Lens for Wide-Angle View
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing single focal length lens systems face challenges in achieving a wide angle of view, compact size, and maintaining optical characteristics stability across temperature variations.
Innovation Solution
A single focal length lens system is designed with a cemented lens having positive optical power and an aspheric joint surface, where the relative refractive index temperature coefficient is controlled to ensure minimal defocusing due to temperature changes, combined with a first unit comprising negative and positive lens elements made of glass and resin, respectively, to achieve a wide angle of view and compact size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a wide-angle lens system is designed with multiple lenses to achieve a wide angle of view, then the angle of view is improved, but the device complexity and size increase
Solution Approach 1:
The patent applies parameter changes by carefully selecting lens materials with specific refractive indices and Abbe numbers, and by optimizing the relative refractive index temperature coefficient (dn/dt) of the cemented lens to satisfy -1.0×10^-5 < dn/dt < 1.0×10^-5. This parameter optimization enables the lens system to maintain excellent temperature characteristics with only six lens elements, resolving the contradiction between temperature stability and device complexity
Solution Approach 2:
The patent uses composite materials by combining different glass types (positive and negative lens elements with different optical properties) into a cemented lens structure. The first positive lens element and second positive lens element are made of different glass materials with specific refractive indices and Abbe numbers, creating a composite optical system that achieves both wide angle of view and temperature stability without increasing overall complexity
2Device complexity
If the lens system is made compact by reducing the number of lenses, then the size is improved, but the ability to maintain optical characteristics across temperature changes deteriorates
Solution Approach 1:
The patent optimizes critical parameters including the relative refractive index temperature coefficient (dn/dt) of the cemented lens, the focal lengths of individual elements, and the spacing between lenses. By satisfying specific parameter ranges (e.g., -1.0×10^-5 < dn/dt < 1.0×10^-5, and various focal length ratios), the system maintains optical characteristics stability with a compact six-element structure
Solution Approach 2:
The patent introduces dynamic compensation for temperature effects by designing the cemented lens with specific positive and negative power elements that counterbalance thermal expansion and refractive index changes. The first and second positive lens elements combined with the negative lens element create a dynamic optical system that automatically compensates for temperature-induced focal length shifts
3Manufacturing precision
If a cemented lens with aspheric surface is used to reduce aberrations, then the manufacturing precision is improved, but the ease of manufacture deteriorates
Solution Approach 1:
The patent applies aspheric surfaces to specific lens elements (the object-side surface of the first positive lens element and the image-side surface of the second positive lens element) to correct spherical aberration and other optical imperfections. The aspheric coefficients are optimized to achieve high manufacturing precision while limiting the number of aspheric surfaces to minimize fabrication complexity
Solution Approach 2:
The patent applies different surface qualities to different parts of the lens system - aspheric surfaces are applied only where needed for aberration correction, while other surfaces remain spherical for easier manufacturing. The cemented lens interface also uses a spherical surface, creating a hybrid design that balances precision and manufacturability
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 lens system provides a significantly widened diagonal angle of view of 150° or more, maintains optical performance across temperature changes from 20 to 80°C, and ensures compact size while reducing aberrations and defocusing.
Implementation Method 1
a joint surface of the cemented lens is an aspheric surface
Implementation Method 2
the cemented lens satisfies the following condition (1): -1.0×10^-5 < dn/dt < 1.0×10^-5, where dn/dt is a relative refractive index temperature coefficient in an atmosphere at 0 to 20°C
Implementation Method 3
a single focal length lens system... includes: a first unit, an aperture diaphragm, and a second unit, wherein the second unit includes a cemented lens having positive optical power
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A single focal length lens system which, in order from an object side to an image side, includes a first unit, an aperture diaphragm, and a second unit is provided. The second unit includes a cemented lens having positive optical power, and a joint surface of the cemented lens is an aspheric surface. The cemented lens satisfies a condition: |dn/dt1|MAX ≤ 2.67× 10-5 (|dn/dt1|MAX: a maximum value of absolute values of relative refractive index temperature coefficients in an atmosphere at 0 to 20°C with respect to light having a wavelength range of 580 to 640 nm, which is calculated for each of lens elements constituting the cemented lens).