Dichroic Light Combiner for Uniform Illumination
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Solution Overview
Problem
Solid-state light sources and narrow-wavelength-band light sources face challenges in optically coupling with light valves in imaging systems, leading to non-uniform illumination and distorted images due to spatial separation of light beams, which results in poor image quality and reduced brightness.
Innovation Solution
An optical system comprising dichroic filters and a reflective surface is used to direct light from multiple light sources, ensuring that the light beams are spatially and angularly coincident, overcoming the limitations of traditional light sources by aligning the principal optical axes and adjusting the tilt angles of the dichroic filters to achieve uniform illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple light sources are used to increase output power, then brightness is improved, but spatial separation of light beams causes distorted illumination field and poor image uniformity
Solution Approach 1:
The patent combines multiple spatially separated light beams from multiple light sources into a single unified beam path using optical elements. The beams are merged in both space and angle to occupy the same optical phase space, eliminating distortion and achieving uniform illumination while maintaining the increased output power from multiple sources.
Solution Approach 2:
The patent introduces intermediary optical elements (such as beam combining optics, mirrors, or waveguides) that mediate between the multiple light sources and the target. These intermediaries redirect and realign the spatially separated beams to converge along the same optical path, resolving the spatial separation issue without requiring the light sources themselves to be physically co-located.
2Area of stationary object
If light sources are arranged to illuminate light valves, then illumination coverage is improved, but spatial separation results in distorted illumination field and reduced image quality
Solution Approach 1:
The patent merges multiple light beams that cover different spatial areas into a single unified illumination path. By combining the beams optically, the system achieves broad illumination coverage from multiple sources while eliminating the spatial separation that would otherwise cause distortion and image quality degradation.
3Device complexity
If solid-state light sources are used, then compact size and durability are improved, but difficulty in optical coupling with light valves occurs due to large solid angle emission
Solution Approach 1:
The patent introduces intermediary optical coupling elements that bridge the gap between solid-state light sources with large solid angle emission and light valves requiring directional illumination. These intermediaries (such as integrating optics, light guides, or beam shaping elements) capture the omnidirectional emission and redirect it into a focused beam path, enabling effective coupling without requiring complex alignment or modification of the solid-state sources themselves.
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 optical system ensures uniform illumination and improved image quality by aligning the light beams from different sources, enhancing brightness and reducing distortions, thereby addressing the challenges of non-uniformity and image quality in imaging systems.
Implementation Method 1
first and second dichroic filters that are substantially-flat and non-parallel for directing light from the light source arrays
Implementation Method 2
a dichroic filter (e.g. a thin film interference filter)
Implementation Method 3
reflecting the light from the second light source by a reflective surface
Data Source
AI summary
For combining light from different light sources in a light source, dichroic filters are displaced individually according to the physical arrangement of the light sources such that the reflected light from the dichroic filters is coincident in angle and space.