Projector System Visible Light Detection Wavelength Filtering
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Solution Overview
Problem
Existing interactive projectors face challenges in distinguishing detection light from image light, requiring high-performance imagers capable of capturing both visible and infrared wavelengths, and lack visual feedback for users due to the use of invisible infrared light for detection.
Innovation Solution
A projector system that uses visible light for detection, allowing the imaging section to differentiate between detection light and image light within the same wavelength band, eliminating the need for infrared light and enabling compact design, with visible light detection light allowing direct visual recognition and simplifying the imaging section's functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If infrared light is used for detection, then the detection light can be distinguished from image light, but the imaging section becomes complex and large-sized due to requiring wide wavelength band capture capability
Solution Approach 1:
The patent changes the wavelength parameter of detection light from infrared to visible light, specifically using blue light (450-480nm) which matches the blue LED light source. This parameter change allows the imaging section to use a standard visible light camera instead of requiring specialized infrared capture capability, thereby reducing device complexity and size while maintaining reliable detection light distinction through wavelength filtering
2Reliability
If infrared light is used for detection, then the detection light can be distinguished from image light, but the system size increases due to infrared illuminator and wide-band imager requirements
Solution Approach 1:
The patent changes the detection light wavelength from infrared to visible blue light, eliminating the need for infrared illuminator and wide-band imager. The system now uses a standard visible light camera module with much smaller volume, while the blue LED light source (450-480nm) provides sufficient detection light without requiring additional infrared illumination hardware
Solution Approach 2:
The patent extracts and removes the infrared-specific components (infrared illuminator, specialized infrared imager) from the system. By using visible blue light for detection, the system only requires a standard visible light camera, thereby taking out the bulky infrared hardware and reducing overall system volume
3Device complexity
If visible light is used for detection, then the imaging section can be simplified and compacted, but the detection light mixes with image light making distinction difficult
Solution Approach 1:
The patent applies local quality by giving the detection light a specific wavelength characteristic (blue light at 450-480nm) that differs from the image light wavelengths. The imaging section uses a bandpass filter tuned to this specific blue wavelength range, allowing the detection light to be distinguished from other wavelengths in the visible spectrum used for image projection, thereby maintaining reliable distinction while using simplified visible light hardware
4Measurement precision
If infrared light is used for detection, then positioning can be performed, but users cannot visually check the detection light directly
Solution Approach 1:
The patent changes the detection light wavelength from invisible infrared to visible blue light (450-480nm). This parameter change allows users to directly see the detection light emitted from the pointing element, providing immediate visual feedback for positioning operations while maintaining the same level of positioning precision through the imaging section's ability to detect the blue light wavelength
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
Enables reliable interactive writing operations by clearly distinguishing detection light from image light, reducing the complexity of the imaging section and providing visual feedback, while eliminating the need for infrared light, thus enhancing user interaction and system simplicity.
Implementation Method 1
an imaging section that receives components within a visible wavelength band different from a wavelength band contained in the image light projected by the projection optical system, the components received as detection light for detection of a position on a projection image
Data Source
AI summary
An imaging section receives, as detection light, the components within a wavelength band different from the wavelength band contained in projection light (image light) that is light containing a visible wavelength band. As a result, even when the detection light and the projection light are each formed of light containing a visible wavelength band, the imaging section can reliably distinguish the detection light from the projection light and therefore detect only the detection light.