Image Sensor Light-Guiding Element for Waving Document Shadow Reduction
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Solution Overview
Problem
Existing image sensors face challenges in maintaining efficient luminous intensity on documents that are waving due to rumples, leading to shadow production and reduced reading performance, and existing solutions either increase costs or complicate light adjustment processes.
Innovation Solution
The image sensor design includes a bar-shaped light-guiding element with first and second light-emitting sections, a lens, and a reflector, along with first and second light-scattering layers, which irradiate light to the document from an oblique direction, ensuring balanced light distribution and reducing shadow formation by adjusting the optical path and scattering patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a shielding member is provided to shield light at a fixed rate, then shadow cancellation is improved, but luminous intensity on the document surface decreases
Solution Approach 1:
The patent applies local quality by providing different light scattering properties at different positions along the light-guiding element. Light scattering patterns are provided at specific areas (remote from light source and at sides) while excluding other areas, creating localized light distribution characteristics that illuminate shadowed areas without requiring uniform shielding across the entire document surface.
Solution Approach 2:
The patent uses light scattering patterns as an intermediary element between the light source and the document. These patterns scatter light in specific directions to illuminate shadowed areas caused by document waving, acting as a mediator that redirects light without requiring physical shielding members that would block light.
2Reliability
If linear lighting apparatus is built in each side of the document, then reading performance of waving document is improved, but cost increases
Solution Approach 1:
The patent makes a single light-guiding element perform multiple functions that would otherwise require separate lighting apparatus. The light-guiding element with strategically positioned light scattering patterns can illuminate both sides of the document effectively, replacing the need for dual-sided linear lighting apparatus while maintaining reading performance for waving documents.
Solution Approach 2:
The patent transitions from a two-sided symmetric lighting arrangement to a single-sided lighting solution by utilizing the light-guiding element's ability to distribute light in multiple directions through the light scattering patterns. This dimensional change in light distribution approach eliminates the need for duplicate lighting apparatus on both sides.
3Stability of the object's composition
If light scattering patterns are provided at all areas, then uniform light emission is improved, but device complexity increases
Solution Approach 1:
The patent achieves uniform light emission through selective rather than universal light scattering. Light scattering patterns are strategically positioned at specific areas (remote from light source and at sides of light-guiding element) where they are most needed to correct non-uniformity, rather than applying scattering patterns across the entire surface.
Solution Approach 2:
The patent applies partial action by providing light scattering patterns only in the specific areas where they are most effective for achieving uniform light emission. This selective approach provides sufficient light uniformity correction without the excessive complexity of covering the entire light-guiding element surface.
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 configuration ensures efficient luminous intensity on the document surface even when shadows are produced, enhancing reading performance without increasing costs or complicating adjustments, and effectively handles document waving due to rumples.
Implementation Method 1
a light source 2a, a bar-shaped light-guiding element 2 extended in a longitudinal direction perpendicular to a space, a first light-scattering layer 3 formed on a surface of the light-guiding element 2 opposite to a center of the light-guiding element 2 of a first light-emitting section 3a
Implementation Method 2
first and second light-scattering layers, which scatter the light in different directions, respectively
Data Source
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AI summary
An image sensor includes a light source (2a) ; a bar-shaped light-guiding element (2) having a first light-emitting section (3a), which propagates light from the light source (2a) and irradiates an document (1) from an oblique direction, and a second light-emitting section (4a) emitting light in a carrying direction of the document (1) ; a lens (6) converging the light reflected from the document (1); a sensor (7) receiving the light passed through the lens (6); a reflector (23) disposed on the opposite side of the light-guiding element (2), by reflecting the light from the second light-emitting section (4a) such that an optical path of the light emitted from the second light-emitting section (4a) is located between the lens (6) and the document (1), and irradiating the document (1) from an oblique direction; and first and second light-scattering layers formed in areas opposed to the first and the second light-emitting sections (3a,4a), respectively, in the light-guiding element (23).