Anamorphic Optical System for High-Intensity Line Imaging

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Solution Overview

Problem

Current imaging systems face challenges in achieving high resolution and high power imaging across large widths in a single pass, particularly in applications like xerographic printing and lithography, due to limitations in optical performance and hardware constraints, which restrict the ability to generate seamless continuous high-resolution images efficiently.

Innovation Solution

An anamorphic optical projection system that concentrates a two-dimensional low-intensity light field into a high-intensity one-dimensional line image, utilizing cylindrical or acylindrical optical elements to achieve high total optical intensity along the entire line image, allowing for reliable high-speed, high-resolution imaging in a single pass.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If a single laser head motorized x-y flatbed architecture is used for large area coverage, then the imaging area is improved, but the imaging speed deteriorates and becomes too slow for high speed printing processes

Engineering Contradiction:
Improveimaging areaVSAvoidimaging speed
Core Design Contradiction:
Area of stationary objectVSProductivity

Solution Approach 1:

The patent divides the imaging system into multiple stationary imaging heads (e.g., three heads) that simultaneously image different portions of the substrate. Each head has its own optical system and laser source, allowing parallel imaging operations that maintain high speed while covering large areas, eliminating the need for slow mechanical scanning of a single head

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent replaces the mechanical x-y scanning system with a stationary multi-head configuration where optical systems remain fixed. The substrate moves continuously through the imaging zone, and multiple stationary heads project images onto different sections simultaneously, eliminating mechanical scanning limitations and achieving both large area coverage and high imaging speed

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Area of stationary object

If LED arrays are used for large width xerography, then the imaging area is improved, but the power output deteriorates and is limited to 10 milliwatt per pixel which is insufficient for high power applications

Engineering Contradiction:
Improveimaging areaVSAvoidpower output
Core Design Contradiction:
Area of stationary objectVSPower

Solution Approach 1:

The patent uses multiple independent laser sources (e.g., three separate laser bars or arrays) instead of a single LED array. Each laser source can be independently controlled and optimized for high power output, while collectively covering the required large imaging area through simultaneous operation and coordinate masking

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from LED technology to laser technology, fundamentally changing the light source parameter from low-power LED emission to high-power laser emission. This enables power outputs in the 10W-100W range per source while maintaining the ability to cover large areas through multi-source coordination and electronic control

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If higher resolution above 1200 dpi is achieved with LED bars, then the image resolution is improved, but the system complexity increases requiring two or more rows of staggered heads

Engineering Contradiction:
Improveimage resolutionVSAvoidsystem complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent divides the high-resolution imaging task across multiple stationary heads, each handling a portion of the total resolution requirement. By coordinating multiple heads with independent control, the system achieves high overall resolution without requiring each individual head to be overly complex, distributing the complexity burden across multiple simpler units

Inventive Principle:
Principle #1Segmentation

4Area of stationary object

If arrayed imaging systems are used to form larger projected images, then the imaging area is improved, but the hardware overhead and alignment requirements increase significantly

Engineering Contradiction:
Improveimaging areaVSAvoidhardware overhead
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent merges multiple imaging heads into a single integrated imaging system that operates as one coordinated unit. The heads share common control electronics, timing synchronization, and substrate transport mechanisms, reducing hardware overhead compared to completely separate systems. The system is designed and manufactured as an integrated assembly, minimizing alignment complexity through precision manufacturing and rigid mechanical structures

Inventive Principle:
Principle #5Merging (Combining)

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 anamorphic optical system enables the generation of high-intensity line images with hundreds of Watts/cm² of optical power, facilitating high-speed, single-pass imaging with resolutions up to 1200 dpi across wide areas, overcoming previous limitations in image resolution and power distribution.

Implementation Method 1

a process-direction optical subsystem including at least one process-direction cylindrical/acylindrical optical element arranged to focus said two-dimensional light field in the process direction on the imaging surface

Methodology Applied
Scientific EffectOptical focusing: Focusing

Implementation Method 2

cross-process optical subsystem including at least one cross-process cylindrical/acylindrical optical element arranged to image said two-dimensional light field in a cross-process direction

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP2561995B1Single-pass imaging system with anamorphic optical system
Publication Date: 2015.02.25 PALO ALTO RESEARCH CENTER INC
  • EP2561995B1 patent drawingFigure 1
  • EP2561995B1 patent drawingFigure 2
  • EP2561995B1 patent drawingFigure 3~4

AI summary

An anamorphic projection optical system is disclosed that takes in a relatively low intensity two-dimensional light field, and anamorphically images and concentrates the light field to generate a substantially one-dimensional, high intensity line image extending in a process direction on an imaging surface. The optical system includes a process-direction optical subsystem (137E) formed by one or more cylindrical/acylindrical lenses (138) in an all-refractive arrangement, or a combination of cylindrical/acylindrical lenses and mirrors to generate the line image with sufficient energy, for example, to evaporate fountain solution from the imaging surface. The anamorphic optical system also includes a cross-process-direction optical subsystem (133E) formed by one or more cylindrical/acylindrical lenses (134E) and an optional cylindrical/acylindrical field lens to image the modulated light field in the cross-process direction. The anamorphic projection optical system facilitates simultaneously generating multiple pixel images of the line image, thus facilitating a printing at 1200 dpi or greater.