Multi-Wavelength Illumination Layout for Shadow-Free Image Reading
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Solution Overview
Problem
Existing illumination devices in image reading apparatuses face challenges in achieving uniform light distribution and efficient irradiation with multiple wavelengths without increasing processing costs or causing shadows due to the arrangement of light emitting diodes (LEDs).
Innovation Solution
The use of a first and second light source with different wavelengths, disposed to intersect their optical axes in an irradiated region, ensuring overlapping light emission to enhance illuminance distribution and prevent shadows, while utilizing a common light source unit to reduce manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple LEDs are arranged in an array to obtain light amount, then illumination intensity is improved, but manufacturing complexity increases due to precise arrangement requirements
Solution Approach 1:
The illumination device is divided into multiple independent LED units arranged in an array, where each LED emits light that contributes to the overall illumination. This segmentation allows independent control and optimization of each light source while achieving uniform illumination through their combined effect.
Solution Approach 2:
Different regions of the illumination surface are optimized by positioning LEDs at specific locations and angles. The light guide is designed with varying thickness or refractive index in different regions to control light distribution, ensuring uniform illumination across the entire surface while simplifying the overall structure.
2Adaptability or versatility
If two types of LEDs are alternately mounted on the same substrate to irradiate light having a plurality of wavelengths, then adaptability is improved, but device complexity increases
Solution Approach 1:
The illumination device uses separate substrates or modules for different wavelength LEDs, with each substrate containing LEDs of a specific wavelength. This segmentation simplifies the mounting process compared to alternating types on a single substrate, while still achieving multi-wavelength irradiation through the combination of multiple modules.
3Stability of the object's composition
If a curved light guide emission surface is used to change emission angle for uniform irradiation, then illumination uniformity is improved, but manufacturing precision requirements increase
Solution Approach 1:
Instead of using a curved light guide emission surface, the patent changes the parameter of light control by using a flat light guide with varying thickness or refractive index. This approach achieves the same illumination uniformity effect while significantly reducing manufacturing precision requirements, as flat surfaces are easier to manufacture with consistent dimensions.
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 provides efficient, uniform light irradiation with different wavelengths, maintaining flatness of illuminance distribution and reducing shadows, thereby enhancing the accuracy and efficiency of image reading.
Implementation Method 1
a first light source and a second light source. The first light source irradiates an irradiation region with a first light in a first direction. The second light source is disposed opposite to the first light source to irradiate the irradiation region with a second light in a second direction.
Data Source
AI summary
An illumination device includes a first light source and a second light source. The first light source irradiates an irradiation region with a first light in a first direction. The second light source is disposed opposite to the first light source to irradiate the irradiation region with a second light in a second direction. The first light is overlapped with the second light in the irradiation region. The first light has a wavelength different from the second light.