Collimating Lens With Flat Diffraction Element
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Solution Overview
Problem
Conventional collimating lenses are costly, large in dimension, and difficult to assemble due to their convex surfaces, which limits their practical application.
Innovation Solution
A collimating lens design featuring at least two lens groups with aspherical surfaces and a flat diffraction lens, fabricated using wafer-level optics, eliminating convex outer surfaces and reducing dimensionality, thereby simplifying assembly and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional mould-made curved glass lens is used, then collimating function is achieved, but cost is high and overall dimension is large
Solution Approach 1:
The collimating lens is divided into multiple lens groups (first lens group with negative powered lens, second lens group with positive powered lens), allowing each group to contribute differently to the collimating function while reducing overall dimension. The segmentation enables compact arrangement of optical elements
Solution Approach 2:
The patent places the diffractive optical element on the image-side surface of the positive powered lens, effectively nesting two optical functions (refraction from lens curvature and diffraction from the DOE) into a single integrated component, reducing overall system dimension
2Reliability
If a conventional mould-made curved glass lens is used, then collimating function is achieved, but cost is high
Solution Approach 1:
The patent combines refractive optical elements (lenses with specific refractive indices and Abbe numbers) with a diffractive optical element in a composite structure, allowing the use of standard glass materials that can be manufactured using conventional techniques, thereby reducing cost while maintaining collimating performance
Solution Approach 2:
By dividing the optical system into separate lens groups that can be manufactured independently using standard glass molding techniques, the patent enables mass production and reduces manufacturing cost compared to creating a single complex curved glass lens
3Reliability
If a conventional lens with convex surface is used, then collimating function is achieved, but assembling is difficult
Solution Approach 1:
Instead of using traditional convex outer surfaces that require precise alignment and mounting, the patent inverts the approach by using aspherical surfaces with specific curvature characteristics that facilitate easier assembly. The aspherical design allows for more tolerant mounting conditions
Solution Approach 2:
The patent employs aspherical surfaces instead of simple spherical or convex surfaces, allowing for optimized curvature profiles that improve both collimating performance and ease of assembly. The aspherical geometry enables better light control while providing surfaces that are more compatible with standard mounting fixtures
4Reliability
If additional glass plates are used to achieve collimation, then collimating function is achieved, but thickness increases
Solution Approach 1:
The patent merges the collimating function with the existing lens groups by incorporating diffractive optical elements on the lens surfaces. This integration eliminates the need for separate collimating glass plates, reducing overall thickness while achieving the same optical function
Solution Approach 2:
The diffractive optical element is nested on the image-side surface of the positive powered lens, combining multiple optical functions (focusing and collimation) into a single integrated component, thereby reducing the number of separate elements and overall system thickness
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 design achieves a compact, cost-effective collimating lens with simplified assembly, enabling efficient alignment of light beams without significant dispersion, and allows for direct patterning of diffractive optical elements on flat surfaces, reducing thickness and eliminating the need for additional glass plates.
Implementation Method 1
a flat diffraction lens disposed nearest to an image plane
Implementation Method 2
at least two lens groups, each having an aspherical surface
Data Source
AI summary
A collimating lens includes at least two lens groups, each having an aspherical surface. The collimating lens also includes a flat diffraction lens disposed nearest to an image plane.