Projector Illumination Module with Offset Foci for Light Mixing Rod
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Solution Overview
Problem
Current projector light sources, such as those emitting red, green, and blue light, differ in source size and emission angle, leading to inefficient illumination of light modulators due to mismatched etendue and aberrations, resulting in suboptimal light coupling and intensity distribution.
Innovation Solution
The illumination apparatus optimizes light coupling by positioning the first and second foci within the light mixing rod at a distance, using standard optical elements and a beam unifier, to maximize etendue transfer and achieve high coupling efficiency, with the first illumination module emitting blue light and the second emitting red or green light, and optionally a third module emitting green or red light, each with specific optical units to converge chief rays into the mixing rod.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If different light sources are used for red, green and blue illumination, then color reproduction is improved, but source size and emission angle differences cause inefficient light coupling
Solution Approach 1:
The illumination system is divided into separate illumination modules for different colors (red, green, blue), each with its own optical unit. This allows optimization of each color's light coupling independently while maintaining overall system functionality. Each module can be designed to match the specific emission characteristics of its light source.
Solution Approach 2:
Each illumination module is equipped with customized optical units (collimators, relay optics, focusing elements) tailored to the specific emission properties of its light source. The optical parameters such as focal length, aperture, and beam shaping are locally optimized for each color's source size and emission angle characteristics.
2Adaptability or versatility
If light sources with different source sizes and emission angles are used, then spectral coverage is improved, but etendue mismatch reduces coupling efficiency
Solution Approach 1:
The optical units are designed with specific parameters (focal lengths, aperture diameters, beam angles) that are optimized for each light source's emission characteristics. By adjusting these optical parameters to match the source's etendue, maximum light coupling efficiency is achieved for each color while maintaining broad spectral coverage.
3Ease of manufacture
If standard optical elements are used, then manufacturing cost is reduced, but optical performance may be compromised
Solution Approach 1:
Standard optical elements (collimators, relay lenses, focusing elements) are used across multiple illumination modules, allowing for manufacturing efficiency and cost reduction. These universal components can be produced using established processes while achieving the required optical performance through proper design and alignment.
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 ensures efficient transfer of luminous flux within the aperture of the optical unit, achieving a compact and cost-effective structure with high coupling efficiency, allowing for uniform illumination of the light modulator and improved image production in projectors.
Implementation Method 1
the first and second imaging optical unit focus the light of the first and second illumination modules, respectively, into the light mixing rod
Implementation Method 2
the light of the light sources is frequently guided through a light mixing rod
Implementation Method 3
an intensity distribution that is as homogeneous as possible is present for the light of each of the light sources
Data Source
AI summary
An illumination apparatus for a projector that includes a light modulator is provided. The illumination apparatus includes a first illumination module emitting first radiation, a second illumination module emitting second radiation, a light mixing rod extending in the axial direction and a superposition unit, which superposes the first and second radiation and couples this into the light mixing rod. The superposition unit includes a first imaging optical unit which focuses the first radiation into the light mixing rod such that a first focus is present, and a second imaging optical unit which focuses the second radiation into the light mixing rod such that a second focus is present. The first focus is spaced apart from the second focus in the axial direction.