Image Reading Device Switching Light Source Periods
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Solution Overview
Problem
Existing image reading devices require separate units for visible and non-visible light, leading to increased costs and difficulties in achieving stable brightness and uniform signal processing due to differing sensitivities of CCDs to these light types, particularly when reading images with fluorescent ink sensitive to ultraviolet light.
Innovation Solution
An image reading device with a light source that switchingly emits visible and non-visible light, controlled by a lighting control mechanism to adjust lighting periods, ensuring that the sensitivity of the image sensor is matched for both types of light, allowing for stable brightness and appropriate signal processing with a single processing means.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate image reading devices are installed for visible light and non-visible light, then image reading capability for different ink types is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines multiple light sources (visible light LED and invisible light UV-LED) into a single light source unit, and uses a single image sensor to detect images under different lighting conditions. This merging approach allows the device to read both regular ink and special ink images without requiring separate reading devices, thereby reducing device complexity while maintaining versatility.
Solution Approach 2:
The image sensor is designed to function universally by detecting both visible light images and invisible light images through switching the light source. The same sensor and processing circuit handle both types of images, making the device multi-functional without requiring separate dedicated devices for different ink types.
2Device complexity
If a single image sensor is used for both visible light and non-visible light, then device complexity is reduced, but brightness stability and signal processing quality deteriorate due to different CCD sensitivities
Solution Approach 1:
The patent dynamically adjusts the lighting conditions by switching between visible light LED and invisible light UV-LED based on the required image type. The lighting control unit activates the appropriate light source before image capture, ensuring optimal brightness and contrast for each light type while using the same image sensor, thereby maintaining brightness stability without increasing device complexity.
3Ease of operation
If uniform lighting time is used for visible light and non-visible light, then device operation is simplified, but image quality deteriorates due to different sensitivities requiring different exposure times
Solution Approach 1:
The lighting control unit implements periodic switching between visible light LED and invisible light UV-LED with different illumination durations. Each light source is activated for a specific time period optimized for its wavelength type, allowing the system to maintain simple operation through automated switching while achieving high image quality through wavelength-appropriate exposure times.
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 device achieves stable brightness and enables effective signal processing for both visible and non-visible light images, reducing the need for separate signal processing circuits and lowering costs by using a single processing unit.
Implementation Method 1
an image sensor for reading the image on the document to output an image signal
Implementation Method 2
in case of reading an image printed with fluorescent ink sensitive to ultraviolet light, the ink is applied with ultraviolet light for causing luminescence
Implementation Method 3
the ink is applied with ultraviolet light for causing luminescence, and the luminescent light is read by the CCD
Data Source
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Figure 3~4
Figure 5(a)~5(g)
AI summary
An image reading device includes: a CCD for reading an image on a document to output an image signal; a light source for switchingly emitting visible light and non-visible light; and lighting control means for controlling lighting periods of the light source. The lighting control means is adapted to perform control such that a first light source lighting period for applying non-visible light is longer than a second light source lighting period for applying visible light. The image reading device also includes splitting means for splitting the image signals outputted from the CCD into an image signal upon application of visible light and an image signal upon application of non-visible light.