LED Scanner Module Light Guide for Uniform Illumination
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Solution Overview
Problem
Legacy scanner modules using CCFL or xenon lamps face issues such as long start-up times, environmental concerns due to mercury, high heat generation, and non-uniform light distribution, which affect image quality and price competitiveness.
Innovation Solution
Employing a light emitting diode (LED) as a light source in conjunction with a light guide member having reflective grooves and guide surfaces to achieve uniform light distribution across the scanning width, reducing start-up time, power consumption, and environmental impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a CCFL is used as a light source, then the scanner module can provide illumination, but it requires a long initial start-up time and contains mercury which is harmful to the environment
Solution Approach 1:
The patent replaces the CCFL with an LED light source that has no mercury content and provides instant start-up. The LED is positioned at one end of the light guide member, eliminating the need for warm-up time and removing environmental hazards associated with mercury-containing lamps.
Solution Approach 2:
The patent changes the light source parameters from CCFL (cold cathode fluorescent lamp) to LED (light emitting diode), fundamentally altering the illumination mechanism. This parameter change eliminates mercury content and reduces start-up time while maintaining adequate illumination for scanning operations.
2Illumination intensity
If a xenon lamp is used as a light source, then the scanner module can provide illumination, but it generates high-temperature heat which degrades image quality
Solution Approach 1:
The patent replaces the xenon lamp with an LED light source that operates at lower temperatures. The LED generates minimal heat compared to the high-temperature xenon lamp, thereby preventing heat-induced image quality degradation while still providing sufficient illumination intensity for scanning.
Solution Approach 2:
The patent substitutes the thermal-based illumination mechanism of the xenon lamp with the electroluminescence mechanism of the LED. This substitution reduces heat generation significantly while maintaining illumination effectiveness, as LEDs convert electrical energy directly to light with minimal thermal byproduct.
3Device complexity
If a point light source with light guide is used, then the scanner module can be compact, but the light distribution across the scanning width becomes non-uniform
Solution Approach 1:
The patent uses the light guide member as an intermediary between the point LED source and the document surface. The light guide member with its specific geometry (width W greater than length L) and optical properties diffuses the point source light into a uniform linear distribution across the scanning width, eliminating the non-uniformity while maintaining compact structure.
Solution Approach 2:
The patent transforms the light distribution from a point source pattern to a linear distribution by utilizing the light guide member's extended geometry. The light guide member converts the zero-dimensional point source into a one-dimensional linear light source that provides uniform illumination across the scanning width, effectively adding a spatial dimension to the light distribution.
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 LED-based scanner module achieves faster start-up, reduced power consumption, improved image quality, and cost-effectiveness with stable light output across a wider temperature range, along with enhanced durability and reduced electromagnetic noise.
Implementation Method 1
a reflective surface 2b formed on the opposite end of the exit surface 2a to reflect and diffuse the light generated from a light source 1
Implementation Method 2
the light generated from the light source 1 may be reflected and diffused by the reflective surface 2b
Implementation Method 3
Employing a light emitting diode (LED) as a light source
Data Source
AI summary
Disclosed are a scanner module and an image scanning apparatus employing the same. The scanner module includes a light source generating light to be irradiated onto an object and a light guide member extending in correspondence with a width of the object to be scanned. The light guide member has a reflective surface for reflecting the light generated from the light source, an exit surface for radiating the light, which is reflected from the reflective surface, toward the object, and a plurality of guide surfaces each guiding the light toward the exit surface by reflecting the light reflected from the reflective surface deviates from the exit surface. The light is effectively guided to be output from the exit surface without substantial light loss.