Near-Infrared Laser Focusing Lens Aberration Correction

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Solution Overview

Problem

Existing focusing lenses for laser printing have a small relative aperture and short working distance, leading to low printing quality and poor color rendition.

Innovation Solution

A near-infrared laser focusing lens is designed with a specific arrangement of five coaxially arranged lenses, including a negative plane-concave lens, positive biconvex lenses, and positive meniscus lenses, optimized for a large relative aperture, long working distance, and flat field, correcting geometrical aberrations to achieve high precision and clarity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of moving object

If a microscope is used as the focusing lens, then the relative aperture can be made large, but the visual field angle becomes small and the working distance becomes short

Engineering Contradiction:
Improverelative apertureVSAvoidworking distance
Core Design Contradiction:
Area of moving objectVSEase of operation

Solution Approach 1:

The focusing lens is divided into five separate lens elements (first lens L1, second lens L2, third lens L3, fourth lens L4, and fifth lens L5) that are coaxially arranged. Each lens element has a specific function: the first lens is a negative plane-concave lens, the second and third lenses are positive biconvex lenses, and the fourth and fifth lenses are positive meniscus lenses. This segmentation allows optimization of multiple parameters simultaneously, achieving large relative aperture, large visual field angle, and long working distance that cannot be achieved with a single microscope lens.

Inventive Principle:
Principle #1Segmentation

2Area of moving object

If a microscope is used as the focusing lens, then the relative aperture can be made large, but the printing quality deteriorates due to small visual field angle and short working distance

Engineering Contradiction:
Improverelative apertureVSAvoidprinting quality
Core Design Contradiction:
Area of moving objectVSManufacturing precision

Solution Approach 1:

The five-lens segmented structure enables independent optimization of each element to correct geometrical aberrations. The specific arrangement with negative plane-concave first lens followed by positive biconvex and meniscus lenses creates complementary optical paths that reduce aberrations while maintaining large aperture, thereby improving printing precision and clarity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each lens element is designed with specific local optical properties: the first lens uses a plane-concave configuration to diverge light, the second and third lenses use biconvex configuration to converge and correct aberrations, and the fourth and fifth lenses use meniscus configuration with middle portions protruding reverse to the transmission direction. This local quality differentiation across lens elements achieves superior imaging quality for near-infrared laser printing.

Inventive Principle:
Principle #3Local quality

3Device complexity

If existing focusing lenses are used, then the device structure can be simple, but the printing precision and clarity are not ideal due to geometrical aberration

Engineering Contradiction:
Improvelens structure complexityVSAvoidprinting precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The five-lens segmented structure, while more complex than a single lens, provides necessary aberration correction capabilities. The segmentation into specific lens types (negative plane-concave, positive biconvex, positive meniscus) with optimized configurations achieves high printing precision that justifies the increased structural complexity.

Inventive Principle:
Principle #1Segmentation

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 provides a clear image with a large visual field and long working distance, enhancing printing precision and clarity, and facilitating operation with true color rendition.

Implementation Method 1

a near-infrared laser focusing lens, as defined in the independent claim, includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens, which are coaxially arranged successively along a transmission direction of an incident light beam

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP2908164B1Near-infrared laser focusing lens and laser printing device
Publication Date: 2018.07.04 HANS LASER TECH IND GRP CO LTD
  • EP2908164B1 patent drawingFigure 1~2
  • EP2908164B1 patent drawingFigure 3~4
  • EP2908164B1 patent drawingFigure 5~6

AI summary

A near-infrared laser focusing lens and a laser printing device are provided. The lens comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens (L1, L2, L3, L4, L5) which are coaxially arranged along a transmission direction of incident light rays, wherein the first lens (L1) is a negative plane-concave lens; the second lens and the third lens (L2, L3) are positive biconvex lenses; and the fourth lens and the fifth lens (L4, L5) are positive meniscus lenses; and a concave surface (S2) of the first lens (L1) is opposite to the second lens (L2), and the middle parts of the fourth lens and the fifth lens (L4, L5) both reversely protrude towards the transmission direction of light beams. After the shapes and the relative locations of the lenses are designed, the near infrared light can be clearly imaged, and the geometrical aberration of the lens can be effectively corrected, so as to obtain a clear flat field. In addition, because of having a large relative aperture and visual field and a long working distance, the lens is a microscope objective simultaneously having a large visual field, a large relative aperture, a long working distance and a flat field, and is capable of improving printing precision and clarity, so that the color rendition is truer and the operation is more convenient.