Light Guide Plate Diffuse Illumination for Uniform Imaging
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Solution Overview
Problem
Existing image capturing devices face challenges in achieving uniform illumination, particularly on reflective or embossed material surfaces, leading to issues like shadow formation and complex lighting setups, especially when capturing images on glossy or transparent film webs.
Innovation Solution
A device with a light guide and at least one light source, where the light is coupled into the light guide to exit diffusely, providing uniform illumination. The light guide can be a flat plate with mirror coating or reflector layers, made of scattering particle materials like transparent polymers, and can be arranged in various configurations to form a compact unit with the detection means, including options for multiple light sources and switching mechanisms for selective illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional lighting setups are used to illuminate reflective or embossed material surfaces, then illumination can be provided, but uniform illumination is difficult to achieve and shadow formation occurs
Solution Approach 1:
A light guide plate is introduced as an intermediary between the light source and the material surface. The light guide plate receives light from a compact LED source and distributes it uniformly across the illumination area through its optical properties, eliminating the need for complex lighting arrangements while achieving shadow-free illumination
Solution Approach 2:
The lighting system changes the spatial distribution parameter of light by using a light guide plate with specific optical properties. The plate transforms point-source light into a distributed diffuse light field, changing the illumination pattern from concentrated to uniform without increasing device complexity
2Illumination intensity
If diffuse illumination is provided using conventional methods, then reflective surfaces can be illuminated, but the device becomes complex and requires significant installation space
Solution Approach 1:
The lighting system is merged with the camera system by integrating the light guide plate directly into the camera housing. The LED source, light guide plate, and camera sensor are combined into a single compact unit, eliminating the need for separate lighting equipment and reducing installation depth
Solution Approach 2:
The light guide plate serves as a compact intermediary that generates diffuse illumination within a small volume. By confining the light distribution function within the plate itself rather than requiring external lighting equipment, the installation space is dramatically reduced
3Illumination intensity
If multiple light sources are used to achieve uniform illumination, then illumination quality improves, but the device complexity increases
Solution Approach 1:
Instead of using multiple light sources, the system changes the optical parameters of a single light source by coupling it with a light guide plate. The plate's optical properties (scattering, total internal reflection) transform the light distribution pattern, achieving uniform illumination equivalent to multiple sources with a single compact LED
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 ensures uniform illumination, prevents shadow formation, and allows for a compact design with flexible application, providing good image quality without the need for complex lighting setups, and enables capturing of different-sized detection areas with varying resolutions.
Implementation Method 1
The light guide means comprises a flat plate... The light guide can be designed in such a way that, with the exception of the surface areas in which the emitted light is coupled in and the surface areas in which the propagating light exits diffusely
Implementation Method 2
The light guide means is made from a material with scattering particles, so that the propagating light exits diffusely in the at least one surface area
Implementation Method 3
the surface areas of the light guide have a mirror coating or reflector layer
Data Source
Figure 1
Figure 2
Figure 2A
AI summary
The device has a detecting unit (210) for detecting an image (200), and an illuminating unit (220) for producing diffused light. The illuminating unit has a light source (222) such as flash tube, which is arranged in such a manner that the light emitted from the light source is coupled and propagated into a light guiding unit (221). The guiding unit is made of a material with scattered particles in such a manner that the light propagated into the guiding unit is diffused and discharged into a surface area (223) of the guiding unit, where the surface area is turned towards the image.