Scanner Illumination Using Dual-Color LED Sets

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Solution Overview

Problem

Conventional scanners using single-color light sources for each exposure have limited scan speed due to reduced illumination, resulting in longer scan times and lower image capture efficiency.

Innovation Solution

The use of two sets of LEDs, such as red and green, and blue and green, for each exposure doubles the illumination, allowing for faster scan times by combining exposures to capture CMY values, which can be converted to RGB, enabling high-quality color image capture at twice the speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If single-color light sources are used for each exposure, then color accuracy is maintained, but scan speed decreases and illumination is reduced

Engineering Contradiction:
Improvecolor accuracyVSAvoidscan speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent combines multiple LED light sources of different colors (red, green, blue) into a single illumination unit that can emit multiple colors simultaneously or sequentially. This merging of light sources doubles the illumination intensity compared to single-color sources, enabling faster scan speeds while maintaining color accuracy through controlled emission sequences and color separation filtering.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent employs periodic emission of different color lights from the combined LED sources, where red, green, and blue LEDs are activated in sequential cycles. During each cycle, specific color combinations are emitted and captured by the sensor array, allowing the system to gather complete color information over multiple periodic exposures while maintaining high illumination intensity throughout.

Inventive Principle:
Principle #19Periodic action

2Device complexity

If single-color LED illumination is used, then color separation is simplified, but illumination intensity is reduced leading to longer scan times

Engineering Contradiction:
Improvecolor separation complexityVSAvoidscan time
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The patent merges multiple colored LED sources into one illumination unit, doubling the total illumination intensity. The color separation function is maintained through the use of color separation filters in the sensor array, which selectively capture red, green, and blue components during periodic emission cycles, thus reducing scan time without significantly increasing overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

3Productivity

If dual-color LED sets are used for each exposure, then illumination is doubled and scan speed increases, but color space conversion complexity increases

Engineering Contradiction:
Improvescan speedVSAvoidcolor space conversion complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent combines red-green and blue-green LED sets to provide dual-color illumination during each exposure, doubling the illumination intensity and enabling faster scan speeds. The increased color space conversion complexity is managed through systematic colorimetric calculations and transformation algorithms that convert the captured dual-color data into standard RGB color space, balancing speed improvement with computational complexity.

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

This approach significantly reduces scan time by doubling the illumination, enabling faster image capture and conversion to RGB color space, enhancing the efficiency and quality of color image scanning.

Implementation Method 1

The use of two sets of LEDs, such as red and green, and blue and green, for each exposure doubles the illumination

Methodology Applied
Scientific EffectLight Emitting Diode: Light Emitting Diode

Implementation Method 2

A sensor array, such as a linear array of CCD or CMOS sensors, reads the scan area

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentEP2979439B1scanner
Publication Date: 2019.07.17 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP2979439B1 patent drawingFigure 1
  • EP2979439B1 patent drawingFigure 2
  • EP2979439B1 patent drawingFigure 3

AI summary

A scanner is disclosed. The scanner captures three exposures for each color scan line. The scanner has a first, second and third light source that each produces a different color of light. The scanner uses the first and second light source for the first exposure. The scanner uses the first and third source for the second exposure. The scanner uses the second and third light source for the third exposure.