Image Reader Lens Array Light Shield Integration

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Solution Overview

Problem

Conventional image readers face challenges in achieving high accuracy and simplicity while avoiding structural complexity and large size, with issues related to the configuration of light guides and lenses, and insufficient details on light sources and positioning in existing designs.

Innovation Solution

The image reader design includes a board with a line sensor assembly and a lens array assembly, where the lens array is supported by a light shield and retained within a transparent member, allowing for efficient light guidance and focusing without the need for a casing, and can utilize a light guide or external light sources, with specific configurations to minimize reflections and enhance illumination efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the light guide and lens array are configured in contact with each other as in conventional designs, then the structure can be compact, but the structural complexity increases and manufacturing details become insufficient

Engineering Contradiction:
Improvedevice sizeVSAvoidstructural complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The patent merges the light guide and lens array into a single integrated unit where the lens array is formed directly on the light guide surface. This integration eliminates the need for separate mounting structures and complex alignment mechanisms, thereby reducing device complexity while maintaining compact dimensions. The merging of these optical components creates a simplified structure that is both space-efficient and easier to manufacture.

Inventive Principle:
Principle #5Merging (Combining)

2Stability of the object's composition

If a casing is used to support the imaging optical system as in conventional designs, then the structural stability is improved, but the device complexity and size increase

Engineering Contradiction:
Improvestructural stabilityVSAvoidcasing structure
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the casing structure from the conventional design. Instead of using a separate casing to support the imaging optical system, the light guide itself serves as the supporting structure. The lens array is directly formed on the light guide, which provides both optical functionality and mechanical support. This extraction of the casing eliminates unnecessary structural elements while maintaining the required stability through the integrated light guide-lens assembly.

Inventive Principle:
Principle #2Taking out (Extraction)

3Illumination intensity

If conventional light source configurations are used, then the illumination can be provided, but the light utilization efficiency is insufficient and reflections occur

Engineering Contradiction:
Improveillumination provisionVSAvoidlight utilization efficiency
Core Design Contradiction:
Illumination intensityVSLoss of energy

Solution Approach 1:

The patent converts harmful reflections into beneficial light guidance. By forming the lens array directly on the light guide surface, the structure utilizes internal reflections and refractions within the light guide to efficiently direct light toward the document. The optical design transforms potential light loss through reflections into effective illumination paths, improving light utilization efficiency while maintaining adequate illumination intensity for image reading.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 design achieves high accuracy in image reading with a simplified structure, reducing the need for a casing and optimizing light utilization, leading to improved image quality and reduced complexity.

Implementation Method 1

light is emitted from light-source elements (point light sources) such as LEDs or organic EL elements, the emitted light is guided through the interior of a light guide (light guiding member) formed of a transparent material

Methodology Applied
Scientific EffectLight guidance: Optical Fibre

Implementation Method 2

a lens array assembly 3 having a plurality of lenses arrayed along the main scanning direction, and focusing the reflected light on the line sensor assembly 4

Methodology Applied
Scientific EffectLight focusing: Lens

Implementation Method 3

image readers receive reflected light from the object-to-be-read through sensor elements, i.e. photosensitive elements, thereby obtaining the image of the object-to-be-read

Methodology Applied
Scientific EffectPhotoelectric conversion: Photoelectric Effect

Data Source

PatentEP2930919B1Image read-in device
Publication Date: 2024.05.22 MITSUBISHI ELECTRIC CORP
  • EP2930919B1 patent drawingFigure 1
  • EP2930919B1 patent drawingFigure 2A~2E
  • EP2930919B1 patent drawingFigure 3~4

AI summary

An image reader configured to focus light emitted from a light source and reflected by an object-to-be-read, and to read an image of the object-to-be-read includes: a board, a line sensor assembly including a plurality of photosensitive elements formed on one surface of the board along a main scanning direction, a lens array assembly including a plurality of lenses arrayed along the main scanning direction, and configured to focus the reflected light onto the line sensor assembly, a light shield configured to support a portion of the lens array assembly at the line-sensor-assembly side or to be in contact with the portion of the lens array assembly at the line-sensor-assembly side, and to block light other than the light focused by the lens array assembly, and a transparent member made of transparent material, formed with a retainer space where the lens array assembly and the light shield are retained, and covering a portion of the lens array assembly at the object-to-be-read side and the light shield.