Variable Divergence Illumination Source with Adjustable Curvature Lens
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Solution Overview
Problem
LED light sources, particularly those with large LEDs or arrays, emit divergent photons with poor spatial correlation, making it difficult to generate a light field suitable for illumination purposes with continuous and monotonic radial intensity distribution.
Innovation Solution
An illumination source comprising an LED light source, a first optical element that generates a second divergent light field with reduced divergence, and a second optical element with a variable lens interface of adjustable curvature, allowing for variable divergence control, which includes light scattering structures to enhance homogeneity and color mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a first optical element is designed to generate a collimated light field from LED light, then the light field processing is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The optical system is divided into two separate optical elements: a first optical element that reduces divergence while maintaining some divergence (α2 ≥ 10°), and a second optical element with variable lens that provides variable focus control. This segmentation allows each element to have a simpler, more specialized design compared to a single complex collimating element.
Solution Approach 2:
The second optical element incorporates a variable lens with adjustable curvature, allowing the system to dynamically adjust the divergence of the output light field. This dynamic capability replaces the need for multiple fixed-focus optical elements, simplifying the overall device while maintaining versatility.
2Productivity
If the second light field is collimated, then the light processing efficiency is improved, but the diameter of the light field at the input side of the second optical element becomes too small
Solution Approach 1:
The first optical element performs only partial collimation, reducing the divergence from the LED's natural high divergence to a moderate divergence angle (α2 ≥ 10°), rather than achieving complete collimation. This partial action is sufficient to improve light processing efficiency while maintaining a large enough beam diameter for the second optical element.
3Device complexity
If the LED light source is used directly, then the device simplicity is maintained, but the spatial correlation and intensity distribution of the light field are poor
Solution Approach 1:
The optical correction function is divided between two elements: the first optical element addresses the high divergence issue by reducing it to a manageable level, while the second optical element with variable lens provides fine-tuned control over the final intensity distribution and divergence. This segmentation achieves good intensity distribution without requiring a single complex optical component.
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 design simplifies the first optical element, facilitates a larger diameter light field, reduces spherical aberrations, and achieves a more homogeneous and monotonically decaying radial intensity in the outgoing light field, suitable for various illumination applications including spotlights with variable divergence.
Implementation Method 1
the first optical element comprises light scattering structures that scatter the light from the light source
Implementation Method 2
a second optical element with a variable lens having a lens interface with variable curvature
Implementation Method 3
the higher refractive section is arranged at a side of the interface facing the led light source. The interface forms, for at least some of the curvatures that it is designed to have, a convex surface of the higher refractive section
Data Source
Figure 1~2
Figure 3
AI summary
The illumination source has a LED light source (2) generating a first divergent light field (6). The light from the LED light source (2) is processed by a first optical element (10), in particular a first lens element, to generate a second divergent light field (19). The first divergent light field (19) is processed by a second optical element (20) having a variable lens variable focus in order to generate a third light field (35) whose divergence can be varied.