Liquid Crystal Polymer Optics for Lidar Signal Collection
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Solution Overview
Problem
Lidar systems face challenges in minimizing component size while maximizing light collection and signal-to-noise ratio, as existing optics do not efficiently achieve high numerical aperture and reduce detector noise.
Innovation Solution
The use of liquid crystal polymer (LCP) optics, which include primary and secondary lenses, gratings, and waveguides, to focus and direct light pulses to photodiodes, enabling higher numerical aperture and integration with photodiode wafers for improved performance and reduced noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the lens diameter is increased to collect more light, then the signal-to-noise ratio is improved, but the device size increases
Solution Approach 1:
The patent implements a nested lens configuration where a secondary lens is positioned within the focal region of a primary lens. The secondary lens receives focused light from the primary lens and further focuses it onto the photodetector array. This nested arrangement allows the system to achieve high numerical aperture and effective light collection equivalent to a much larger single lens, while maintaining a compact overall device footprint.
2Area of stationary object
If the focal length is minimized to reduce detector size, then the device size is reduced, but the light collection ability decreases
Solution Approach 1:
The patent divides the optical focusing function into two separate components: a primary lens that performs initial light collection and focusing, and a secondary lens that performs additional focusing onto the photodetector array. This segmentation allows each lens to be optimized for its specific function, enabling the system to achieve high numerical aperture and effective light collection while maintaining a compact detector size and short overall focal length.
3Measurement precision
If liquid crystal polymer optics are used to achieve high numerical aperture, then the light collection ability is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent utilizes liquid crystal polymer (LCP) material properties, specifically its ability to exhibit high refractive index and controllable optical characteristics. By changing the material parameter (refractive index) through selection of LCP, the system achieves high numerical aperture without requiring complex optical designs or additional optical elements, thereby simplifying the overall manufacturing process despite the specialized material used.
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
LCP optics facilitate a higher achievable numerical aperture, reduce detector size and noise, and offer cost-effective, lightweight, and versatile solutions for lidar systems, enhancing light collection and signal quality.
Implementation Method 1
The numerical aperture (NA) of a lens is a measure of its focusing and light collection ability. NA can be calculated using the equation n*sin(θ), where n is the refractive index of the lens
Implementation Method 2
The LCP grating is configured to receive and direct the light pulses, and the at least one photodiode is positioned to receive the light pulses from the LCP grating
Data Source
AI summary
A detector for use in detecting reflected or scattered light pulses for a lidar system includes a primary lens, a secondary lens, and a photodiode array. The primary lens is configured to collect and focus the light pulses, the secondary lens is configured to receive and further focus the light pulses from the primary lens, and the photodiode array is configured to receive and sense the light pulses from the secondary lens. At least one of the primary lens or the secondary lens are configured using liquid crystal polymer (LCP).