Fixed Focal Length Lens Aberration Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Designing a projection lens that balances high image quality, low distortion aberration, high resolution, high contrast, and uniform image illumination while minimizing size and cost is challenging due to conflicting design requirements, such as achieving a large field of view and reducing distortion aberration, which often results in increased length and complexity with the use of multiple lenses.
Innovation Solution
A fixed focal length lens configuration comprising a first lens group with negative and positive refractive powers, a second lens group with positive refractive powers, and a third lens group with a single positive refractive power, allowing for internal focusing and reducing the number of lenses to minimize size and cost while maintaining good imaging quality and a large field of view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the field of view is increased to project a large image within a short distance, then the projection capability is improved, but the distortion aberration increases and the lens size increases
Solution Approach 1:
The projection lens is divided into multiple lens groups (first lens group with negative refractive power, second lens group with positive refractive power, and third lens group with positive refractive power) arranged in sequence. Each lens group contributes to correcting different types of aberrations while maintaining the overall large field of view capability, thereby resolving the contradiction between wide FOV and distortion control.
Solution Approach 2:
Aspheric surfaces are applied to specific lenses (at least one lens in the first lens group and at least one lens in the second lens group) rather than uniformly across all lenses. This localized application of aspheric design allows for precise correction of distortion aberration in critical regions while maintaining the overall optical performance and large field of view.
2Manufacturing precision
If glass aspheric lenses are used to achieve high imaging quality and low distortion aberration, then the image quality is improved, but the cost increases
Solution Approach 1:
Aspheric surfaces are applied selectively to only certain lenses (at least one lens in the first lens group and at least one lens in the second lens group) rather than all lenses. This localized approach achieves the necessary aberration correction and high imaging quality while significantly reducing manufacturing cost compared to making all lenses aspheric.
Solution Approach 2:
The lens system is segmented into different groups with different refractive powers, allowing the aspheric surfaces to be strategically placed in groups where they provide the most benefit for aberration control, while other groups can use simpler spherical lenses, thus balancing performance and cost.
3Ease of manufacture
If spherical lenses are used to reduce cost, then the manufacturing cost is reduced, but the number of lenses must exceed 9 which increases the lens size
Solution Approach 1:
The projection lens is divided into three lens groups with specific refractive power configurations (negative, positive, positive). This segmentation allows for more efficient optical design that achieves the required imaging performance with fewer total lenses (6 lenses) compared to conventional designs that would require over 9 spherical lenses, thereby reducing both size and cost.
Solution Approach 2:
By applying aspheric surfaces to specific lenses in strategic positions within the lens groups, the optical performance is enhanced enough that fewer total lenses are needed to achieve the same or better imaging quality, thus reducing the overall lens size while maintaining cost-effectiveness.
4Illumination intensity
If the chief beam angle is reduced to improve light efficiency and illumination uniformity, then the illumination uniformity is improved, but the telecentric angle becomes smaller which conflicts with the large field of view requirement
Solution Approach 1:
The lens system is divided into three functional groups that work together to simultaneously achieve a small telecentric angle (within ±3 degrees) for good illumination uniformity and a large field of view (30 degrees or more). Each group contributes to balancing these competing requirements through its specific refractive power and positioning.
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 configuration achieves a balance of high image quality, low distortion aberration, and a large field of view with a small telecentric angle, while reducing the overall size and cost by using fewer lenses and incorporating aspheric and spherical lenses strategically.
Implementation Method 1
a first lens group disposed between the magnified side and the reduced side and having a positive refractive power, the first lens group including a first lens and a second lens arranged in sequence from the magnified side towards the reduced side, and having refractive powers respectively negative and positive
Data Source
AI summary
A fixed focal length lens including a first lens group, a second lens group, and a third lens group arranged in sequence from a magnified side towards a reduced side is provided. The first lens group has a positive refractive power, and includes a first lens and a second lens arranged in sequence from the magnified side towards the reduced side. Refractive powers of the first lens and the second lens are respectively negative and positive. The second lens group has a positive refractive power, and includes a third lens, a fourth lens, and a fifth lens arranged in sequence from the magnified side towards the reduced side. Refractive powers of the third lens, the fourth lens, and the fifth lens are respectively positive, negative, and positive. The third lens group has a positive refractive power, and includes a sixth lens. A refractive power of the sixth lens is positive.