Lighting Device Non-Overlapping Rod Integrator Regions
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Solution Overview
Problem
Current projection type image display apparatuses face challenges in achieving high brightness and image quality due to the limitations of LEDs, which have poor light-converging efficiency and wide spectral distribution, leading to increased size and cost, and decreased color purity.
Innovation Solution
A lighting device comprising a first and second light source section, with a light combining section that uses a non-overlapping incident surface area for each light source, employing laser elements and LEDs, and a fluorescent material excited by a blue laser beam to produce red and green fluorescent light, while maintaining a high divergence angle to reduce etendue and enhance light output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple LED light sources are arranged and optically combined to increase light output, then the amount of light is improved, but the etendue increases in proportion, requiring an image display apparatus with high etendue that increases size and cost
Solution Approach 1:
The patent divides the light combining section into multiple independent light receiving regions (first region and second region) that do not overlap. Each region receives light from corresponding light source sections, allowing independent optimization of each path while maintaining overall high light output without proportionally increasing etendue.
Solution Approach 2:
Different light source sections (first and second) are assigned to different non-overlapping regions on the light combining section. This local assignment allows each light source to be optimized for its specific region, improving light output efficiency without requiring the entire system to accommodate the maximum etendue of any single source.
2Illumination intensity
If a fluorescent material is used to convert blue laser beam into green light, then green light brightness is increased, but the spectral distribution extends over a wide wavelength range, decreasing color purity
Solution Approach 1:
The patent uses separate light source sections for different colors (first light source section for red and green, second light source section for blue). This segmentation allows each light source to be optimized for its specific wavelength, avoiding the spectral broadening problem of fluorescent conversion while maintaining high brightness output.
Solution Approach 2:
The patent combines light from multiple light source sections (red LED, green LED, blue laser) in the light combining section. By merging these independently optimized light sources, the system achieves high brightness while maintaining color purity, as each source contributes its narrow spectral distribution without requiring fluorescent conversion.
3Duration of action of stationary object
If LEDs are used as light sources for projection type image display apparatuses, then long service life and high light-emission efficacy are achieved, but poor light-converging efficiency and broad light-emitting surface area prevent effective use
Solution Approach 1:
The patent introduces a light combining section as an intermediary optical element that receives light from multiple LED light source sections and consolidates it into a unified output. This intermediary structure enables effective light convergence from the broad-emitting-area LEDs, transforming their poor light-converging efficiency into effective projection illumination.
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 brightness and image quality with a compact and cost-effective projection type image display apparatus by efficiently combining light from different sources, reducing etendue, and stabilizing light output, thereby improving color purity and visibility.
Implementation Method 1
a fluorescent material excited by a blue laser beam to produce red and green fluorescent light
Data Source
AI summary
A lighting device is provided which efficiently achieves a high brightness and a high image quality by using a solid light source which has long service life and does not need mercury. The lighting device includes a first light source section, a second light source section, a second rod integrator for combining lights emitted from the first and second light source sections, and a first rod integrator for guiding the light from the first light source section, to the second rod integrator. On an incident surface of the second rod integrator, a first region on which the light emitted from the first light source section is incident and a second region on which the light emitted from the second light source section is incident do not overlap each other, and the surface area of the first region and the surface area of the second region are different from each other.