Lidar Sensor Module with Microlens Array for Resolution Robustness
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Solution Overview
Problem
Lidar microscanner systems face challenges in achieving precise beam deflection and resolution due to tolerances in scanning beam deflection units, leading to reduced maximum resolution and detection reliability, as the angle of deflection is not unequivocally assignable to a defined object point in the field of view.
Innovation Solution
A module for a lidar sensor is introduced, featuring a light transmitting path with a movable mirror and a microlens set-up where the spot diameter of the first light beam is predefined, ensuring that only one microlens is illuminated, reducing tolerance susceptibility and maintaining angular robustness, with the microlens set-up positioned between the light transmitting path and the objective to guide the light beam to a defined point in the field of view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a scanning beam deflection unit (mirror galvanometer or micromirror) is used to deflect the transmitted beam, then the system can achieve beam expansion and increased robustness, but the tolerance of the scanning unit causes uncertainty in the angle of deflection, reducing maximum resolution and detection reliability
Solution Approach 1:
The patent divides the optical system into distinct functional segments: a light transmitting path that generates a light beam with a predefined spot diameter, and a microlens set-up that receives this beam. The segmentation allows the light beam to be treated as a separate entity with controlled properties that can be independently optimized, decoupling the resolution from the scanning unit tolerances.
Solution Approach 2:
The patent changes the critical parameter from the angle of deflection (which is sensitive to scanning unit tolerances) to the spot diameter of the light beam (which is predefined by the light transmitting path). This parameter change makes the system's resolution dependent on the controllable spot diameter rather than on the tolerances of the scanning beam deflection unit.
2Measurement precision
If the spot diameter of the light beam is reduced to illuminate only one microlens, then the assignment of light beams to microlenses becomes unique and resolution improves, but the light beam must be precisely controlled which increases system complexity
Solution Approach 1:
The light transmitting path is designed in advance to generate a light beam with a predefined spot diameter that is larger than the microlens diameter. This preliminary configuration ensures that the light beam properties are established before reaching the microlens set-up, simplifying the overall system design by pre-defining critical parameters rather than controlling them dynamically.
3Reliability
If the spot diameter of the light beam is increased to improve robustness against local soiling, then eye safety and robustness increase, but adjacent microlenses may be illuminated which reduces resolution
Solution Approach 1:
The patent applies local quality by making the spot diameter of the light beam locally larger than the microlens diameter. This local enlargement of the spot ensures that the light beam can tolerate local soiling on the objective lens while still maintaining unique assignment to a specific microlens, as the spot's predefined diameter ensures it illuminates only one microlens at a time.
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 ensures uniform resolution and increased detection reliability by ensuring that each light beam illuminates a specific microlens, reducing the impact of tolerances and maintaining eye safety through additional beam expansion, allowing for a compact and robust lidar sensor construction.
Implementation Method 1
the microlens set-up being situated downstream from the light transmitting path... the light transmitting path is configured, in particular, to illuminate a first microlens of the microlens set-up from the input side, using a first light beam whose spot diameter is predefined
Implementation Method 2
A unit of a sensor, which may be integrated structurally and functionally in the sensor, is presently understood as a 'module.' The module contains a light transmitting path, which includes a light source, e.g., a laser source, and a movable mirror, e.g., a mirror galvanometer and/or a micromirror
Data Source
AI summary
A module for a lidar sensor, including: a light-transmitting path having a movable mirror and a light source; and a transmitting-side microlens set-up, which is situated downstream from the light transmitting path; the light transmitting path being configured to illuminate a first microlens of the microlens set-up on the input side, using a first spot of a predefined diameter of a first light beam; the predefined diameter of the spot of the first light beam being greater than a diameter of the first microlens, and a distance of an edge of the first microlens to edges of adjacent microlenses inside of the transmitting-side microlens set-up corresponding to a difference between the predefined diameter of the spot of the first light beam and the diameter of the first microlens.