Light-Guiding Element for Homogeneous Document Illumination

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Solution Overview

Problem

Existing document detection systems face challenges in achieving homogeneous illumination while minimizing installation space, especially when capturing documents of different formats, which often requires a large number of lighting devices and increased space for multiple spectral ranges.

Innovation Solution

A device utilizing a flat light-guiding element, such as a foil-like light guide, where light is coupled in and out through a first surface to illuminate the document, allowing for efficient and homogeneous illumination with reduced space requirements, and incorporating a surface structure with raised areas to direct light for optimal beam steering and decoupling regions for improved contrast.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a large number of lighting devices are used to achieve homogeneous illumination, then illumination quality is improved, but installation space requirement increases

Engineering Contradiction:
Improvehomogeneous illumination qualityVSAvoidinstallation space
Core Design Contradiction:
Illumination intensityVSVolume of stationary object

Solution Approach 1:

Multiple light sources are integrated into a single light-guiding element structure, where individual LEDs are positioned at specific locations (corners and center) but function as a unified illumination system through the light guide, reducing the number of separate lighting devices while maintaining homogeneous illumination

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The light-guiding element acts as an intermediary between the light sources and the document surface, distributing light uniformly across the illumination area through its optical properties and geometric design, thereby achieving homogeneous illumination with fewer direct light sources

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If multiple spectral ranges are used for optical detection, then detection capability is improved, but device complexity increases

Engineering Contradiction:
Improvespectral detection rangeVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The light-guiding element is designed to support multiple spectral ranges (UV, visible, IR) by incorporating light sources across these ranges, allowing a single illumination system to serve multiple detection purposes without requiring separate lighting subsystems for each spectral range

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

Solution Approach 2:

The illumination system is segmented into discrete light sources positioned at specific locations (corners and center), each potentially emitting different spectral ranges, allowing independent optimization of each segment while maintaining overall system simplicity

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 solution enables homogeneous illumination of documents with reduced space usage, minimizing reflections and improving optical detection quality, allowing for easy integration into existing systems while maintaining high-resolution imaging.

Implementation Method 1

couple light into a flat light-guiding element, in particular a foil-like light-guiding element (2), and to couple out the coupled-in light on a first surface (3) for illuminating the document

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

The light-guiding element (2) has a first surface (3)... light is coupled in and out through a first surface to illuminate the document

Methodology Applied
Scientific EffectLight coupling: Refraction

Implementation Method 3

incorporating a surface structure with raised areas to direct light for optimal beam steering

Methodology Applied
Scientific EffectBeam steering: Refraction

Implementation Method 4

The reflected light can then be optically detected to generate the desired image of the surface structure of the document

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3120535B1Device and method for optically detecting a document and method for fabrication of said device
Publication Date: 2020.09.23 BUNDESDRUCKEREI GMBH
  • EP3120535B1 patent drawingFigure 1~2
  • EP3120535B1 patent drawingFigure 3

AI summary

The invention relates to an apparatus and a method for optically detecting a document (9), wherein the apparatus (1) has or forms at least one receiving volume having a resting surface (11) for the document (9) to be detected, wherein the apparatus (1) comprises at least one lighting device (7), wherein the apparatus (1) comprises at least one light-guiding element, wherein the light-guiding element has a first surface (3), wherein, by means of the lighting device (7), light can be coupled into the light-guiding element and can be coupled out of the light-guiding element towards the receiving volume in the region of the first surface (3). Furthermore, the invention relates to a method for producing the above-mentioned apparatus.