Image Projection Apparatus Reflective Phosphor Arrangement
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Solution Overview
Problem
Existing image projection technologies using laser-diode light sources and phosphors face low light transformation efficiency and output power when using transmissive phosphors, and struggle to maintain color balance due to variations in excitation light brightness and phosphor life.
Innovation Solution
An image projection apparatus employing a first and second light source with planar wavelength conversion elements, where the optical-path lengths and planes of the converted lights are equivalent and orthogonal, and at least one optical axis is not on the same plane as the converted light axes, utilizing reflective phosphors to enhance luminous efficiency and reduce component count.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If transmissive phosphors are used in light-source devices, then the device structure is simpler, but the light transformation efficiency becomes low
Solution Approach 1:
The patent inverts the conventional transmissive phosphor structure by using reflective phosphors instead. The reflective phosphors are positioned to reflect light back through the exit pupil, converting excitation light to fluorescent light with higher efficiency, thereby resolving the contradiction between structural simplicity and light transformation efficiency.
Solution Approach 2:
The patent introduces a spatial dimension by arranging reflective phosphors at specific positions and orientations (orthogonal planes with equivalent optical-path lengths). This dimensional arrangement optimizes light reflection paths and maintains color balance while improving overall luminous efficiency.
2Power
If reflective phosphors are used to improve light transformation efficiency, then the output power increases, but the device complexity increases
Solution Approach 1:
The patent employs asymmetric arrangement of reflective phosphors on orthogonal planes rather than symmetric configurations. This asymmetric design optimizes light reflection paths for different colors while maintaining equivalent optical-path lengths, achieving high output power without excessive complexity.
Solution Approach 2:
The patent creates equipotential optical paths by ensuring that the optical-path lengths from the excitation light source through the reflective phosphors to the exit pupil are equivalent. This equalizes the optical conditions for different color channels, simplifying the overall system design while maintaining high output power.
3Stability of the object's composition
If the optical paths of fluorescent lights from paired phosphors are made equivalent, then the color balance is maintained, but the device complexity increases
Solution Approach 1:
The patent applies equipotentiality by designing optical paths with equivalent lengths for fluorescent lights from different reflective phosphors. This ensures that color balance is maintained despite variations in excitation light brightness or phosphor aging, as all color channels experience equivalent optical conditions.
Solution Approach 2:
The patent resolves color balance requirements by transitioning to a three-dimensional orthogonal plane arrangement. By positioning reflective phosphors on orthogonal planes with carefully controlled optical-path lengths, the system maintains color stability without requiring complex two-dimensional adjustments.
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 solution achieves high output power with reduced size and prevents blurring or mottling, maintaining color balance and optimizing phosphor efficiency by using reflective phosphors and carefully arranging optical components.
Implementation Method 1
a first planar wavelength conversion element to convert the first excitation light into a light of a different specific wavelength, and a second planar wavelength conversion element to convert the second excitation light into a light of a specific wavelength different from the specific wavelength of the first excitation light converted by the first planar wavelength conversion element
Data Source
AI summary
An image projection apparatus includes a first light source to emit a first excitation light of a specific wavelength, a second light source to emit a second excitation light of a specific wavelength, a first planar wavelength conversion element to convert the first excitation light into a light of a different specific wavelength, and a second planar wavelength conversion element to convert the second excitation light into a light of a specific wavelength different from the specific wavelength of the first excitation light converted by the first planar wavelength conversion element. In the image projection apparatus, the first planar wavelength conversion element and the second planar wavelength conversion element are arranged at positions different from each other, and the first planar wavelength conversion element and the second planar wavelength conversion element have a first plane and a second plane.