Scanner Module Diffusion Plate Uniform Illumination
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Solution Overview
Problem
Current scanner modules using light emitting diodes (LEDs) suffer from uneven light distribution, leading to brighter centers and dimmer ends, which affects scanning quality and amplifies noise, despite firmware compensation attempts to improve uniformity.
Innovation Solution
A diffusion plate with interlaced second transverse convex and concave portions is used to receive and diffuse incident beams from LEDs, ensuring uniform light distribution over the scanned object, enhancing image brightness and signal-to-noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a fluorescent tube or LED light strip is used as a light emitting device, then the light source can illuminate the document, but the brightness is not uniform with the middle part being brighter and the two ends being dimmer
Solution Approach 1:
The patent applies local quality by varying the density arrangement of light transmitting portions and light reflecting portions at different locations on the light guiding member. Specifically, the light transmitting portions are arranged with different densities in different regions to compensate for the inherent brightness non-uniformity of LED light strips, making the middle and end regions have appropriate light transmission characteristics to achieve overall uniform illumination.
Solution Approach 2:
The patent changes the physical parameters of the light guiding member by adjusting the density, size, and distribution of light transmitting portions and light reflecting portions. By modifying these parameters spatially, the patent transforms the non-uniform light output from LEDs into uniform illumination across the scanned object surface.
2Illumination intensity
If firmware compensation is used to increase the brightness of the two ends, then the brightness uniformity is improved, but the signal/noise ratio is degraded and noise is amplified
Solution Approach 1:
The patent applies preliminary action by pre-adjusting the light distribution through the specific arrangement of light transmitting and reflecting portions in the light guiding member before the scanning process. This physical pre-compensation eliminates the need for firmware compensation, thereby avoiding noise amplification while achieving brightness uniformity.
3Illumination intensity
If a fog-like diffusion plate is used to diffuse light uniformly, then the brightness uniformity is improved, but the light intensity is greatly decreased resulting in low image brightness
Solution Approach 1:
The patent applies segmentation by dividing the light guiding member into multiple functional regions with light transmitting portions and light reflecting portions arranged in a segmented pattern. This segmented structure allows selective light transmission and reflection to achieve uniformity without the light loss associated with fog-like diffusion plates.
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 significantly reduces image distortion and increases scanning quality by providing uniform light to the scanned object, improving the signal-to-noise ratio and overcoming the limitations of conventional fog-like diffusion plates.
Implementation Method 1
a plurality of light emitting diodes (LEDs), positioned on the substrate and adapted to generate a plurality of incident beams
Implementation Method 2
a diffusion plate, corresponding to the plurality of LEDs, adapted to receive the plurality of incident beams and diffuse the plurality of incident beams to a scanned object uniformly
Data Source
AI summary
A light projecting apparatus of a scanner module, including: a substrate, a plurality of light emitting diodes (LEDs), positioned on the substrate and adapted to generate a plurality of incident beams; a diffusion plate, corresponding to the plurality of LEDs, adapted to receive the plurality of incident beams and diffuse the plurality of incident beams uniformly over a scanned object and including: a first plane, receiving the plurality of incident beams; two end faces; connected to the two ends of the first plane in a transverse direction; and a second plane, the two ends thereof being respectively connected to the two end faces, adapted to diffuse the plurality of incident beams uniformly over the scanned object and including: a plurality of second transverse concave portions, adapted to diffuse the plurality of incident beams; and a plurality of second transverse convex portions, adapted to gather the plurality of incident beams, where the plurality of second transverse convex portions and the plurality of second transverse concave portions are interlaced in a transverse direction, allowing the plurality of incident beams to be diffused uniformly over the scanned object.