Erecting Equal-Magnification Lens Array Plate Stray Light Control
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Solution Overview
Problem
Erecting equal-magnification lens array plates in image reading devices suffer from flare noise due to stray light reflections and refractions, which degrade the signal-to-noise ratio and image quality, especially when manufacturing or assembly errors cause light to reach unintended areas.
Innovation Solution
The solution involves a stacked configuration of lens array plates with light shielding walls and a roughened surface on areas outside the effective lens regions to scatter stray light, reducing flare noise. The plates are formed by injection molding with high light transmittance materials, and the roughening process has a center-line average surface roughness of 0.2-2 μm to effectively manage stray light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If light shielding walls are provided to block stray light, then ghost noise is reduced, but manufacturing precision requirements increase due to alignment errors causing flare noise
Solution Approach 1:
The patent applies the principle of converting harm into benefit by roughening surfaces that would otherwise cause harmful flare noise. Specifically, the light shielding wall surfaces, lens array plate surfaces, and housing inner surfaces are intentionally roughened to scatter stray light that escapes through manufacturing alignment errors, converting the harmful reflection/refraction into beneficial scattering that prevents flare noise formation
2Loss of energy
If multiple columns of rod lenses are used to improve light transmission, then light transmission proportion increases, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges multiple lens array plates (first lens array plate with first and second lenses, second lens array plate with third and fourth lenses) into a single integrated optical system. This combination achieves the light transmission benefits of multiple lens columns while simplifying the overall structure and reducing manufacturing complexity compared to using separate rod lens columns
Solution Approach 2:
The lens array plates serve multiple functions simultaneously: they focus light from the line light source, create erect equal-magnification images, and when combined with roughened surfaces, they also scatter stray light to prevent flare noise. This multi-functionality reduces the need for separate components
3Volume of moving object
If erecting equal-magnification optics are used instead of reduction optics, then device size is reduced, but stray light control becomes more difficult
Solution Approach 1:
The patent applies local quality by selectively roughening specific surfaces (light shielding wall surfaces, lens array plate surfaces, and housing inner surfaces) while keeping other surfaces smooth. This localized surface treatment targets areas where stray light is most problematic, effectively controlling stray light in the compact erecting optics configuration without compromising overall device size benefits
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 significantly reduces flare noise by scattering stray light, improving the signal-to-noise ratio and image quality, with experimental results showing a 30-50% reduction in flare noise compared to unmodified plates.
Implementation Method 1
At least one of an area on the first surface outside the effective region of the first lenses, an area on the second surface outside the effective region of the second lenses, an area on the third surface outside the effective region of the third lenses, an area on the fourth surface outside the effective region of the fourth lenses, an area of the first light shielding wall facing the first surface, and an area of the second light shielding wall facing the fourth surface is roughened
Implementation Method 2
the erecting equal-magnification lens array plate receives light from a line light source facing the first surface and forms an erect equal-magnification image of the line light source on an image plane facing the fourth surface
Data Source
AI summary
An erecting equal-magnification lens array plate includes a stack of a first lens array plate provided with a plurality of first lenses arranged on a first surface and a plurality of second lenses arranged on a second surface, and a second lens array plate provided with a plurality of third lenses arranged on a third surface and a plurality of fourth lenses arranged on a fourth surface. The erecting equal-magnification lens array plate is provided with a first light shielding wall provided upright to surround the first lens, and a second light shielding wall provided upright to surround the fourth lens. An area on the first surface of the first lens array plate outside the effective region of the first lenses is roughened.