Fluorophore Wheel Illumination Optical System for Compact Projectors
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Solution Overview
Problem
The existing illumination optical systems for projectors, as described in Patent Document 1 and Patent Document 2, face an issue where the light paths of blue light differ from those of red and green light due to transmission and reflection processes, leading to increased system size and complexity.
Innovation Solution
The proposed illumination optical system incorporates a fluorophore unit with a reflection region and fluorophore regions, along with a quarter-wave plate and a dichroic mirror that separates and guides polarized light components, allowing blue, green, and red light to share the same optical path, reducing the number of optical components and system size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If blue light is transmitted through the fluorophore wheel while red and green light are reflected, then wavelength-specific light paths are established, but the optical system size and component count increase
Solution Approach 1:
The patent merges the light paths of blue light (reflected from reflection region) and fluorescent light (emitted from fluorophore regions) by using a beam splitter to combine them into a common optical path. This eliminates the need for separate optical systems for different wavelengths, reducing overall system size and component count while maintaining reliable wavelength-specific light path separation.
Solution Approach 2:
The fluorophore wheel is designed to serve multiple functions simultaneously: it acts as both a wavelength converter (converting blue light to red and green fluorescent light) and a beam splitter (separating and directing different wavelengths through different regions). The reflection region and fluorophore regions work together to provide universal light path management for all color channels, reducing the need for additional dedicated components.
2Ease of operation
If separate optical systems are used for blue light and fluorescent light, then light path control is simplified, but the number of optical parts increases
Solution Approach 1:
The beam splitter merges the separately controlled light paths of reflected blue light and emitted fluorescent light into a single common optical path. This maintains the simplicity of wavelength-specific control while reducing the total number of optical parts by eliminating redundant components in separate light paths.
3Volume of stationary object
If a compact illumination optical system is achieved by sharing optical paths, then system size is reduced, but light path design complexity increases
Solution Approach 1:
The fluorophore wheel is segmented into distinct functional regions: a reflection region for blue light and fluorophore regions for red and green light emission. This segmentation allows each region to be optimized for its specific function while working together in a compact configuration, reducing overall system size without excessively complicating the light path design.
Solution Approach 2:
The beam splitter acts as an intermediary optical element that facilitates the merging of light paths from different regions of the fluorophore wheel. It simplifies the light path design by providing a clear, wavelength-based routing mechanism that directs reflected blue light and emitted fluorescent light into a common path without requiring complex optical arrangements.
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 enables a compact illumination optical system with fewer parts by ensuring that all colored light passes through the same optical path, enhancing efficiency and reducing the overall size of the projector.
Implementation Method 1
a fluorophore that, by the irradiation of light of the first wavelength, emits fluorescent light of a wavelength that differs from the first wavelength
Implementation Method 2
a reflection region that reflects light of the first wavelength
Implementation Method 3
a quarter-wave plate that is provided on the light path between the optical element and the fluorophore unit
Implementation Method 4
The optical element separates light of the first wavelength into a first linearly polarized light component and a second linearly polarized light component that is orthogonal to the first linearly polarized light component
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
An illumination optical system having fewer constituent parts and smaller size is provided. The illumination optical system includes: a light source (11 or 41) emitting light of a first wavelength; a fluorophore unit (16); an optical element (13 or 43) and a quarter-wave plate (14) between the optical element and the fluorophore unit. The fluorophore unit has a reflection region and a fluorophore region that gives off fluorescent light of a different wavelength than the first wavelength when irradiated by light of the first wavelength. The fluorophore unit is able to move such that the light from the light source sequentially irradiates the fluorophore region and the reflection region. The optical element separates the light of the first wavelength into a first linearly polarized light component and a second linearly polarized light component that is orthogonal to the first linearly polarized light component. The optical element guides the first linearly polarized light component of the light emitted from the light source to the fluorophore unit, and emits the light of the first wavelength that was reflected by the reflection region and fluorescent light that was emitted by the fluorophore region in the same direction.