Double-Telecentric Projection Optical System Chromatic Aberration Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing double-telecentric projection optical systems face issues with insufficient correction of longitudinal chromatic aberration and difficulty in maintaining telecentricity when using multiple wavelength bands, leading to unsatisfactory performance across various applications.
Innovation Solution
A double-telecentric projection optical system is designed with a specific lens group configuration, including a first lens group with positive power, a second lens group with negative power, and a third lens group with positive lenses, satisfying certain focal length ratios and refractive index conditions to efficiently correct chromatic aberrations and maintain telecentricity across a range of wavelengths from the visible region to near ultraviolet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional achromatic lens system is used for double-telecentric projection, then the system can be constructed with basic lens elements, but longitudinal chromatic aberration is insufficiently corrected
Solution Approach 1:
The optical system is divided into three distinct lens groups (first with positive power, second with negative power, third with positive power) arranged in sequence. Each group contains specific numbers of lenses with defined power characteristics, creating a segmented structure that enables independent optimization of chromatic aberration correction for each group while maintaining overall system performance.
Solution Approach 2:
Different regions of the optical system are assigned different optical properties: the first and third lens groups use positive power lenses to converge light and correct chromatic aberration, while the second lens group uses negative power lenses to diverge light and balance the system. The stop is positioned within the third group to control aperture and reduce aberrations locally.
2Adaptability or versatility
If a double-telecentric optical system is designed to work with multiple wavelength bands, then versatility is improved, but chromatic aberration increases
Solution Approach 1:
The optical system is designed with lens groups and elements that simultaneously correct chromatic aberration across multiple wavelength bands (g-line, h-line, i-line). The combination of positive and negative power lenses in specific configurations enables the system to handle different wavelengths effectively, making it universal for various inspection and measurement applications requiring multi-wavelength operation.
Solution Approach 2:
The system utilizes lenses with specifically selected refractive indices and dispersion characteristics (Abbe numbers) to correct chromatic aberration across different wavelengths. By changing the optical parameters of the lens materials and their arrangements, the system achieves achromatization for multiple wavelength bands while maintaining double-telecentricity.
3Device complexity
If the optical system is simplified to reduce complexity, then ease of manufacture is improved, but telecentricity cannot be maintained
Solution Approach 1:
The system is segmented into three functional lens groups with a stop, where each group has a specific role in maintaining telecentricity. The first positive power group establishes initial ray convergence, the negative power group provides divergence to balance the system, and the third positive power group with the stop ensures final telecentric output. This segmentation allows telecentricity to be maintained through the coordinated function of simplified groups rather than requiring a single complex lens element.
Solution Approach 2:
The stop acts as an intermediary element within the third lens group, controlling the aperture and regulating the chief rays to pass through the optical center. This intermediary component is crucial for maintaining double-telecentricity by ensuring that principal rays are parallel to the optical axis at both object and image spaces, while the lens groups provide the necessary power distribution.
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 system effectively corrects chromatic aberrations, particularly longitudinal chromatic aberration, while maintaining telecentricity and desired projection magnification, ensuring smooth ray travel and minimizing aberrations across multiple wavelengths.
Implementation Method 1
a first lens group with a positive power, including a first lens arranged at a closest position to the enlargement side in the projection optical system; a second lens group with a negative power, including a lens or lenses which start with a negative lens
Data Source
AI summary
The projection optical system uses a plurality of wavelengths or a wavelength band within a wavelength range from a visible region to a near ultraviolet region. The double-telecentric projection optical system includes: a first lens group with a positive power; a second lens group with a negative power, including a predetermined lens or lenses; and a third lens group with a positive power, including a stop and at least two positive lenses satisfying a predetermined condition relating to refractive index. The projection optical system satisfies a predetermined condition relating to a composite focal length of the first lens group and the second lens group, and a focal length of the third lens group.