Projection Device Light Shield and Diaphragm Stray Light Control
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Solution Overview
Problem
Existing projection technologies face challenges in accurately capturing and projecting visible light images based on captured invisible light images, particularly in medical settings where fluorescent images are weak and difficult to visualize.
Innovation Solution
A projection device comprising an invisible image sensor, a projector, a visible image sensor, an imaging optical system, a light guide, and a light shield, which captures and projects visible light images by regulating light quantities and minimizing interference, ensuring accurate visualization of invisible light images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the diaphragm value is adjusted to capture more light for better visible light image quality, then the visible light image brightness is improved, but the depth of field decreases causing focus issues
Solution Approach 1:
The patent applies parameter changes by adjusting the diaphragm value to an optimized range (F1.8 to F2.8) that balances light intake and depth of field requirements. This specific parameter optimization resolves the contradiction by finding the optimal operating point where sufficient visible light is captured while maintaining adequate depth of field for accurate focus in augmented reality projection.
2Device complexity
If the optical path is simplified to reduce system complexity, then device complexity is reduced, but stray light interference increases affecting image accuracy
Solution Approach 1:
The patent introduces a light shield as an intermediary element positioned at the optical path from the light guide to the imaging optical system. This light shield blocks stray light without requiring complex optical path modifications, thus resolving the contradiction by eliminating harmful stray light interference while maintaining relative simplicity of the overall optical system.
Solution Approach 2:
The patent extracts and removes the harmful component (stray light) from the optical system by positioning a light shield to block stray light paths. This extraction approach eliminates the harmful factor without adding significant complexity to the system, resolving the contradiction between system simplicity and stray light prevention.
3Volume of moving object
If the light guide is positioned closer to the imaging optical system to compact the device, then device size is reduced, but stray light from the light guide increases
Solution Approach 1:
The patent positions a light shield as an intermediary between the light guide and the imaging optical system. This light shield blocks stray light generated by the light guide, allowing the light guide to be positioned closer to the imaging optical system for device compactness without suffering from increased stray light interference.
Solution Approach 2:
The patent extracts the harmful stray light from the optical path by introducing a light shield that blocks stray light from the light guide. This allows the light guide to be positioned close to the imaging optical system for compact device design while removing the harmful stray light effect.
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 precise and accurate capturing and projection of visible light images, enhancing visualization of surgical sites by reducing stray light and improving image contrast, thus aiding medical procedures.
Implementation Method 1
The light guide is configured to guide light to enter the imaging optical system and to guide light exited from the projector
Implementation Method 2
The diaphragm has a diaphragm value set so that a length difference between an optical length from a near point in a depth of field of the imaging optical system to the imaging optical system and an optical length from the light shield to the imaging optical system
Implementation Method 3
The invisible image sensor is configured to capture an invisible light image indicating a subject in invisible light
Implementation Method 4
The visible image sensor is configured to capture an image of the subject onto which the projection image is projected with visible light
Implementation Method 5
The projector is configured to project a projection image onto the subject with visible light, the projection image being based on the invisible light image
Data Source
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AI summary
A projection device (200) includes an invisible image sensor (211), a projector (220), a visible image sensor (212), an imaging optical system (215), a light guide (201), and a light shield (202). The invisible image sensor captures an invisible light image of a subject. The projector projects a projection image based on the invisible light image onto the subject with visible light. The visible image sensor captures an image of the subject onto which the projection image is projected. The system includes a diaphragm (214). The light guide guides light to enter the system and light exited from the projector. The light shield is disposed at a space from the light guide. A diaphragm value is set so that a length difference between an optical length from a near point in a DOF of the system and an optical length from the light shield is longer than a front DOF from the subject.