Dual-Lens LED Collimator for Projection Displays
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Solution Overview
Problem
Existing projection display systems face challenges in efficiently collimating light from Lambertian sources like LEDs without degrading the etendue, requiring complex and costly lens systems due to alignment issues.
Innovation Solution
A two-element collimator system comprising a hemispherical or hyperhemispherical ball lens and a converging lens, such as a Fresnel lens, in direct contact with each other, positioned between the light source and the spatial light modulator to converge and collimate light efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a series of lenses are used to image the LED source onto the DMD, then the light can be collimated, but the alignment becomes extremely difficult and expensive
Solution Approach 1:
The patent combines multiple lens functions into a single integrated optical element. The meniscus lens is molded with an aspherical surface that performs both collimation and etendue preservation functions that would otherwise require multiple separate lenses, eliminating alignment issues between multiple components
Solution Approach 2:
The patent uses an aspherical surface design with specific radius of curvature values (R1 and R2) and conic constants to optimize the optical parameters. By changing the surface geometry from spherical to aspherical, the system achieves better collimation and etendue preservation while maintaining ease of manufacture through single-element molding
2Illumination intensity
If the emission angle is reduced onto the DMD, then the light is better collimated, but the etendue is degraded making the image blurred
Solution Approach 1:
The aspherical surface parameters (radius of curvature, conic constant) are specifically optimized to control light ray angles. The surface profile equation with variable curvature allows precise control of the emission angle reduction while maintaining etendue conservation, preventing image blur
Solution Approach 2:
The patent transitions from spherical to aspherical surface geometry. The aspherical surface provides variable curvature that can be optimized to control light propagation angles more precisely than a spherical surface, achieving both collimation and etendue preservation
3Adaptability or versatility
If multiple lenses are used in the optical path, then the light manipulation is more flexible, but the device complexity increases
Solution Approach 1:
The patent merges multiple optical functions into a single meniscus lens element. The aspherical surface provides collimation, etendue preservation, and aberration correction that would otherwise require multiple separate lenses, simplifying the overall device while maintaining functional flexibility
Solution Approach 2:
The aspherical meniscus lens serves multiple functions simultaneously: collimating light, preserving etendue, and correcting optical aberrations. This multi-functional single element replaces what would traditionally require multiple specialized lenses
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 system effectively reduces light source emission angle while preserving etendue, enhancing image brightness and luminance with easier and more cost-effective production by ensuring precise alignment and minimizing aberration.
Implementation Method 1
The first lens may be a hemispherical orhyperhemispherical ball lens
Implementation Method 2
the second lens may include a converging lens such as a Fresnel lens
Implementation Method 3
the second lens may include a converging lens such as a Fresnel lens
Data Source
AI summary
A system and method for collimating light emitted from a light source, such as a light-emitting diode (LED), is provided. The system and method includes two lenses, both lenses having a positive power for converging the light rays. In one example, the first lens is a hemispherical ball lens and the second lens is configured such that one surface conforms to the exiting surface of the first lens. The exiting surface of the second lens may be, for example, a Fresnel lens or an aspherical lens. In another example, the first lens may be a hemispherical or a hyperhemispherical ball lens. The second lens has an outer circumference having two aspherical surfaces. The inner portion of the second lens is in direct contact with the first lens. This configuration creates a dual-channel collimator.