Document Detection System Using Illumination Microlens Array

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Solution Overview

Problem

Existing document detection systems face challenges in achieving homogeneous illumination and efficient, complete detection of large documents while maintaining a flat profile, leading to difficulties in correcting brightness and requiring extensive microlens arrays and sensors that are not technically feasible.

Innovation Solution

A document detection system utilizing an illumination microlens array coupled with imaging microlens arrays, where light sources are arranged in a grid between optical sensors to ensure homogeneous illumination, with each microlens array aligned and mechanically connected to prevent misalignment, allowing for pixel-precise illumination and imaging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If a microlens array is used to reduce system depth, then the structural depth is reduced to less than 1 mm, but it becomes difficult to achieve homogeneous illumination and capture large-area documents

Engineering Contradiction:
Improvestructural depthVSAvoidhomogeneous illumination
Core Design Contradiction:
Length of stationary objectVSIllumination intensity

Solution Approach 1:

The patent divides the illumination system into multiple discrete light sources arranged in a grid pattern between the document and the sensor array. Each light source illuminates a specific region, and the combined effect provides homogeneous illumination across the entire document area while maintaining the flat profile of the microlens array system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent positions light sources at specific locations between the document and optical sensors, creating localized illumination zones that collectively cover the entire document area. This allows each region to receive optimized illumination while maintaining the overall flat structure.

Inventive Principle:
Principle #3Local quality

2Area of stationary object

If multiple optical sensors are used to capture large documents, then the detection coverage is increased, but the system complexity and difficulty of achieving homogeneous illumination increase

Engineering Contradiction:
Improvedetection coverageVSAvoidsystem complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent combines multiple optical sensors arranged in a grid into a unified detection system with a corresponding grid of light sources. The sensors work together to capture the entire document area, and the light sources are coordinated to provide uniform illumination across all sensor fields of view, simplifying the overall system architecture.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a modular system where each sensor-light source pair can function independently for its designated region, yet all components work together as a unified system. This multi-functional approach allows the system to capture large documents while maintaining manageable complexity through standardized modular units.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Illumination intensity

If light sources are arranged between optical sensors, then homogeneous illumination is achieved, but precise alignment is required to avoid misalignment

Engineering Contradiction:
Improvehomogeneous illuminationVSAvoidalignment precision
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent integrates the light sources and optical sensors into a nested configuration where light sources are positioned in the spaces between sensors at defined distances from the document. This nested arrangement naturally maintains alignment relationships and reduces the need for high-precision mechanical alignment during assembly.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent pre-establishes the geometric relationships between light sources and sensors through fixed mounting structures and defined spacing. This preliminary configuration of alignment relationships simplifies the assembly process and reduces the precision requirements during final assembly, as the alignment is built into the system architecture rather than requiring post-assembly adjustment.

Inventive Principle:
Principle #10Preliminary action

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

Enables fast, reliable, and complete detection of documents with homogeneous illumination, reducing the need for extensive correction calculations and facilitating the integration of the system into a flat format, while ensuring optimal alignment and efficient use of light sources.

Implementation Method 1

imaging optics comprising a microlens array for imaging the document on the optical sensor or sensors. In this case, the microlens arrays are arranged on or formed directly on a spacer layer

Methodology Applied
Scientific EffectLight refraction and focusing through microlens arrays: Lens

Implementation Method 2

at least one optical sensor and imaging optics for imaging the document on the at least one optical sensor

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP2165315B1Document recording system, and document recording method
Publication Date: 2014.09.10 BUNDESDRUCKEREI GMBH
  • EP2165315B1 patent drawingFigure 1~2
  • EP2165315B1 patent drawingFigure 3~4
  • EP2165315B1 patent drawingFigure 5~6

AI summary

The invention relates to a method for recording documents as well as a document recording system (1) for optically recording a document (2). Said document recording system (1) comprises at least one illuminant (15, 15', 15") for illuminating the document (2), at least one optical sensor (6, 6'), and a projection lens (8) for representing the document (2) on the at least one optical sensor (6, 6'). The at least one illuminant (15, 15', 15") is coupled to an illuminating lens system (16) which allows the document (2) to be illuminated as homogeneously as possible.