Lenslet Array Illumination System Reducing Alignment Sensitivity
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Solution Overview
Problem
Existing illumination systems employing collimated light sources, such as laser sources, require precise alignment between light sources and optical components, which can be costly and complex, and often suffer from speckle noise degrading image quality.
Innovation Solution
The use of a lenslet array and an optical homogenizer in an illumination system where each collimated light beam covers a portion of multiple lenslets, providing uniform illumination and reducing sensitivity to alignment errors, while also incorporating a homogenizer to minimize speckle noise through expanded light beam focusing at multiple focal points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If collimated light sources are used in illumination systems, then high intensity and directional light output are achieved, but precise alignment between light sources and optical components is required which increases system complexity and cost
Solution Approach 1:
The illumination system divides the collimated light beam into multiple separate beams using a lenslet array, where each lenslet creates a distinct focal point. This segmentation allows the system to tolerate misalignment better, as each localized beam can be independently controlled and focused, reducing the overall alignment sensitivity of the system.
Solution Approach 2:
The patent introduces an intermediary optical element (the lenslet array or homogenizer) between the collimated light source and the final illumination target. This intermediary component converts the sensitive collimated light into a more robust illuminated pattern through multiple focal points, acting as a mediator that decouples the alignment sensitivity from the final illumination quality.
2Illumination intensity
If collimated light sources are used, then high intensity illumination is achieved, but speckle noise degrades image quality
Solution Approach 1:
The lenslet array segments the collimated light beam into multiple spatially separated focal points. This segmentation disrupts the coherent interference patterns that cause speckle noise, as each focal point contributes independently to the overall illumination pattern, thereby reducing speckle while maintaining high intensity.
Solution Approach 2:
The patent changes the spatial distribution parameter of the light by transforming it from a single-mode collimated beam into a multi-mode focused pattern with multiple focal points. This parameter change in the light's spatial structure eliminates the coherent interference that causes speckle noise while preserving the high intensity characteristic of collimated sources.
3Productivity
If precise alignment is maintained, then optimal light delivery is achieved, but system cost and complexity increase
Solution Approach 1:
The lenslet array creates multiple focal points that are spaced apart, which beforehand cushions the system against alignment errors. If misalignment occurs, the multiple focal points ensure that at least some light is delivered to the correct region, preventing complete failure of light delivery and reducing the need for extremely precise alignment.
Solution Approach 2:
The system changes the sensitivity parameter of light delivery by transforming the single-point focus into a multi-point distribution. This parameter change reduces the gradient of light intensity with respect to position, making the system less sensitive to alignment variations while maintaining overall delivery efficiency.
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 allows for uniform and high-intensity illumination with reduced need for precise alignment, minimizing speckle noise and enabling the use of less expensive, smaller components, resulting in improved image quality and system cost-effectiveness.
Implementation Method 1
a lenslet array for receiving and expanding the emitted light. Each discrete light beam in the emitted light has an intensity full width at half maximum (FWHM) at the lenslet array that covers at least a portion of a plurality of lenslets in the lenslet array
Implementation Method 2
an optical element. The optical element receives the transmitted light from an input face of the optical element. The optical element further homogenizes the received light and transmits the homogenized light from an output face of the optical element
Data Source
AI summary
An optical system and a projection system incorporating same are disclosed. The optical system includes a light source that is capable of emitting light. The emitted light includes one or more substantially collimated discrete light beams. The optical system further includes a lenslet array for receiving and transmitting the emitted light. Each discrete light beam in the emitted light has an intensity full width at half maximum (FWHM) at the lenslet array that covers at least a portion of a plurality of lenslets in the lenslet array. The optical system further includes an optical element for receiving the transmitted light from an input face of the optical element. The optical element homogenizes the received light and transmits the homogenized light from an output face of the optical element.