Concave Reflector White Light Generation for Projectors
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Solution Overview
Problem
Current projector systems are inefficient in generating white light, leading to significant light wastage and limited color gamut, as they rely on traditional methods that do not effectively concentrate and combine blue light with broad band light to produce a wide range of colors.
Innovation Solution
The system improves white light generation by mounting blue laser diodes on a flat plate, directing blue light through a concave reflector to create a collimated beam, which is then combined with broad band light emitted from a phosphor target, using a recycling optic and reflective material to enhance light collection and efficiency, and optionally incorporating red and green laser diodes to expand the color gamut.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional white light generation methods are used in projector systems, then the system structure is simple, but light efficiency is low and significant light is wasted
Solution Approach 1:
The system segments the white light generation process into distinct functional modules: blue laser diodes mounted on a flat plate generate blue light, a concave reflector concentrates and collimates this light, a phosphor wheel converts portion of the blue light to yellow-green broad band light, and a beam combiner merges the remaining blue light with the broad band light to produce white light. This modular segmentation improves light efficiency by optimizing each stage while managing system complexity through organized functional separation.
Solution Approach 2:
The patent employs a concave reflector to transform the spatial distribution of blue light from the laser diodes, concentrating divergent rays into a collimated beam. This dimensional transformation of light propagation paths increases light collection efficiency and directs light precisely where needed, reducing waste while maintaining a compact system layout.
2Adaptability or versatility
If blue light is directly combined with broad band light without concentration, then the system is simple, but the color gamut is limited and spectral color range is narrow
Solution Approach 1:
A concave reflector with curved surface is used to concentrate and collimate blue light from the laser diodes. This curvature enables efficient light collection and directional control, creating a focused beam that can be effectively combined with phosphor-generated broad band light to expand the spectral color range and color gamut beyond what simple direct combination could achieve.
Solution Approach 2:
The system uses a phosphor wheel that converts a portion of blue light to yellow-green broad band light, changing the spectral parameters of the light. By combining this spectrally transformed light with the remaining blue light, the system achieves an expanded color gamut and spectral color range, meeting the enhanced adaptability requirement.
3Productivity
If light from laser diodes is not concentrated, then the system configuration is simple, but light capture efficiency is low
Solution Approach 1:
The concave reflector is positioned to preliminarily concentrate and collimate blue light from the laser diodes before the light reaches the phosphor wheel and beam combiner. This preliminary concentration action ensures that maximum light intensity is achieved at each subsequent stage, improving overall light capture efficiency while the modular design keeps the optical system manageable in complexity.
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 increases the spectral color range, matches or exceeds the output of a 4 kW Xenon lamp in digital cinema projectors, and expands the color gamut by 25%, while improving light capture efficiency and reducing system complexity and cost.
Implementation Method 1
directing the blue light rays emitted from the blue laser diodes towards a concave reflector, which then concentrates the blue light rays back towards the flat plate into a hole where the blue light rays are collimated into a beam of blue light
Implementation Method 2
The beam of blue light is then directed towards a phosphor target, which when excited by the blue light emits a broad band light in the yellow-green range
Implementation Method 3
Broad band light rays that are emitted from a collection region on the phosphor target are then collected by a collection lens where the broad band light rays are collimated into a broad band light beam
Implementation Method 4
a recycling optic may be positioned adjacent to the phosphor target. The recycling optic is configured and positioned in a manner that allows broad band light emitted from the phosphor target that is not directed towards a collection region to be reflected by the recycling optic to increase the probability that the emitted light will eventually escape the recycling optic and enter a collectable zone
Data Source
AI summary
A system and method of generating white light for a projection system in a compact form factor using laser diodes, a reflection system, and a phosphor target. Light emitted from the laser diodes can be directed towards a region of the phosphor target, where the phosphor target is excited and emits light in a desired spectrum in all directions. Some emitted light is collected by a collection lens. The emitted light collected by the collection lens can be combined with light from the original laser diodes to create white light for use in the projection system. Light emitted in a direction away from the collection lens can be redirected to the collection lens by the reflection system that employs a curved reflector on one side of the phosphor target and a flat reflector on the opposite side of the phosphor target.