Illumination Device Shared Light Path Wavelength Selecting Unit
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Solution Overview
Problem
Conventional image projection devices require two separate light paths for excitation and fluorescent light, limiting the downsizing of illumination devices due to the need for distinct pathways that do not overlap.
Innovation Solution
An illumination device with a light source, a fluorescence generating unit, a wavelength selecting unit, a polarization converting unit, and a light guiding unit, where the wavelength selecting unit alternates between allowing source light and fluorescent light to pass through, enabling both lights to share a common light path and reducing the device's size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If two separate light paths are used for excitation light and fluorescent light, then the light paths can be clearly distinguished and controlled, but the illumination device size cannot be reduced
Solution Approach 1:
The patent merges the excitation light path and fluorescent light path into a single shared light path. The wavelength selecting unit acts as a dynamic switch that alternates between directing excitation light to the phosphor and directing fluorescent light to the light tunnel, eliminating the need for two separate physical paths and reducing device size.
Solution Approach 2:
The wavelength selecting unit dynamically switches between different light path configurations based on the type of light being transmitted. It alternates between a first state for excitation light and a second state for fluorescent light, enabling a single static structure to perform multiple functional roles that would otherwise require separate static paths.
2Reliability
If separate light paths are used for excitation and fluorescent light, then light interference is avoided, but the device structure becomes more complex and larger
Solution Approach 1:
The wavelength selecting unit periodically switches between transmitting excitation light and transmitting fluorescent light in alternating cycles. This time-division multiplexing approach ensures that only one type of light occupies the shared path at any given moment, preventing light interference while using a single compact structure.
Solution Approach 2:
The wavelength selecting unit serves as an intermediary component that mediates between the light source/phosphor and the light tunnel. It selectively directs different wavelengths of light through the same physical space at different times, maintaining light path isolation without requiring physically separate paths.
3Volume of moving object
If two light paths bypass each other, then light interference is minimized, but the device cannot be downsized
Solution Approach 1:
The patent combines the excitation light path and fluorescent light path into one shared optical path, allowing both types of light to traverse the same physical components (lenses, mirrors, etc.) but at different times. This merging eliminates redundant components and reduces device size while the wavelength selecting unit prevents light loss by ensuring only the appropriate light type passes through at any moment.
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
This configuration allows for the downsizing of image projection devices while maintaining brightness by eliminating the need for separate light paths and reducing light loss, thus improving the projection's efficiency and image quality.
Implementation Method 1
a fluorescence generating unit configured to generate fluorescent light by use of the source light from the light source as excitation light, the fluorescent light having a longer wavelength than the source light
Implementation Method 2
a polarization converting unit disposed in a light path between the light source and the wavelength selecting unit and configured to convert polarization of light between linear polarization and circular polarization such that a first linear polarization component input thereto is converted into circular polarization and circular polarization input thereto is converted into a second linear polarization component perpendicular to the first linear polarization component
Data Source
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AI summary
An illumination device includings: a light source (11) configured to emit source light; a fluorescence generating unit (16,18) configured to generate fluorescent light by use of the source light from the light source (11) as excitation light; a wavelength selecting unit ((13) configured to alternately place either a first segment or a second segment in a light path, the first segment allowing the source light to pass therethrough, and the second segment reflecting the source light while allowing the fluorescent light to pass therethrough; a polarization converting unit (14) configured to convert polarization of light between linear polarization and circular polarization; and a light guiding unit (15, 17) configured to guide a first linear polarization component and the fluorescent light to the polarization converting unit (14) and to guide a second linear polarization component to the fluorescence generating unit (16, 18).The object is to downsize an illumination device.