Scanner Illumination Module Using Composite Light Sources
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Solution Overview
Problem
Scanners face limitations in speed due to non-uniform illumination, with prior solutions like center attenuation being inefficient as they waste light and fail to achieve uniform illumination across the scanning field.
Innovation Solution
A scan module employing a combination of a primary lamp and a secondary light source, such as LEDs, positioned to provide additional illumination, ensuring more uniform light distribution across the scan field by reflecting light through an optical slit and detected by an image sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If scanner speed is increased, then productivity is improved, but illumination intensity must be increased which leads to greater light attenuation at edges
Solution Approach 1:
The patent applies local quality by using different light sources with different spectral characteristics in different regions of the scanning field. Specifically, a first light source (e.g., xenon lamp) illuminates the center region while a second light source (e.g., LED) illuminates the edge region. This allows each region to receive optimized illumination tailored to its specific requirements, compensating for the natural vignette effect at edges without requiring uniform intensity increase across the entire field.
2Illumination intensity
If center attenuation is applied to achieve uniform illumination profile, then illumination uniformity is improved, but light efficiency deteriorates due to light wastage
Solution Approach 1:
Instead of uniformly attenuating light across the entire field (which wastes energy), the patent applies local quality by selectively illuminating different regions with different light sources. The edge region receives additional illumination from a second light source optimized for that region, achieving uniformity without the need to wastefully attenuate the center region's light.
Solution Approach 2:
The patent changes the spectral parameters of illumination by using two different light sources with different emission characteristics. The first light source provides broad-spectrum illumination for the center, while the second light source provides targeted illumination for the edges. This parameter change allows efficient use of light energy while achieving the desired uniform illumination profile.
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 enhances scanner speed by maintaining consistent illumination intensity across the scanning field, reducing light wastage and achieving a more efficient illumination profile compared to traditional methods.
Implementation Method 1
at least one lamp positioned to illuminate at least a portion of the scan field, and a second light source positioned to provide additional illumination for the portion of the scan field
Implementation Method 2
light from the elongated lamp and the second light source is reflected from the document
Data Source
AI summary
A scan module including an image sensor defining a scan field, at least one lamp positioned to illuminate at least a portion of the scan field, and a second light source positioned to provide illumination for the portion of the scan field.