ToF LiDAR Beam Steering With Switchable LCPG Gratings
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Solution Overview
Problem
Mechanical systems for altering light direction in time of flight (ToF) LIDAR systems are complex and inefficient.
Innovation Solution
A non-mechanical ToF LIDAR system using an electrically switched grating assembly with switchable liquid crystal polarized gratings (LCPGs) and optical metasurfaces to alter beam direction, enabling multiple directed beams without mechanical components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If mechanical means are used to alter light transmission direction in ToF LIDAR systems, then the direction can be changed to measure multiple regions, but the system becomes complex and inefficient
Solution Approach 1:
The patent replaces mechanical means with a non-mechanical approach using a switchable liquid crystal polarized grating (LCPG) that uses electrical switching to alter light transmission direction. The LCPG consists of a liquid crystal plate and a polarized grating plate that work together to deflect light along different transmit axes based on the liquid crystal's orientation, eliminating moving mechanical parts while maintaining the ability to measure multiple regions.
Solution Approach 2:
The patent changes the optical parameters of the light transmission system by using a switchable liquid crystal polarized grating that can alter the transmission direction through electrical switching. By changing the orientation of the liquid crystal molecules via applied voltage, the system dynamically adjusts the transmission axis without mechanical movement, thereby reducing complexity while preserving adaptability.
2Adaptability or versatility
If mechanical means are used to alter light direction, then multiple regions can be measured, but the system size increases
Solution Approach 1:
The patent eliminates mechanical components by using an electrically controlled liquid crystal polarized grating system. This substitution removes the need for bulky mechanical actuators, motors, and moving parts, thereby significantly reducing the system volume while maintaining the capability to measure multiple regions through electrical switching of the LCPG.
3Adaptability or versatility
If mechanical means are used to change beam direction, then multiple target regions can be accessed, but efficiency decreases
Solution Approach 1:
The patent replaces slow mechanical movement with rapid electrical switching of the liquid crystal polarized grating. The LCPG can instantly change transmission direction by altering the liquid crystal orientation through voltage control, eliminating mechanical inertia and movement time, thereby significantly improving system efficiency while maintaining access to multiple target regions.
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 achieves efficient and compact beam direction changes, reducing complexity and size while maintaining accuracy in distance measurement and target property sensing.
Implementation Method 1
a switchable liquid crystal polarized grating (LCPG) positioned to intercept and divert, by a common angle, both the outgoing collimated light along the transmit axis and the incoming light along the receive axis
Implementation Method 2
a switchable liquid crystal (LC) plate configured to provide a switchable retardation to the outgoing collimated light and the incoming light
Implementation Method 3
the receiver consists of a single detector that receives light from a metasurface, and the metasurface is configured to focus the incoming light to the single detector
Implementation Method 4
a transmitter, configured to transmit outgoing collimated light toward a target along a transmit axis; the transmitter consists of a single radiator that radiates light to a metasurface, and the metasurface is configured to produce the collimated light
Implementation Method 5
A time of flight (ToF) system, using light, measures the time taken for light to travel from a transmitter to an object and return. From the known speed of light, the distance to the object can be calculated from the measured time
Data Source
AI summary
A system for optical sensing, consisting of a transmitter that transmits outgoing collimated light toward a target along a transmit axis, and a receiver, positioned alongside the transmitter, that receives incoming light propagating from the target along a receive axis parallel to the transmit axis and that outputs electrical signals in response to the received incoming light. The system includes a switchable liquid crystal polarized grating (LCPG) positioned to intercept and divert, by a common angle, both the outgoing collimated light along the transmit axis and the incoming light along the receive axis, the common angle being selectable from among a plurality of preset diversion angles of the LCPG. A controller switches the LCPG over the preset diversion angles and processes the electrical signals output by the receiver in response to the incoming light received at the preset diversion angles so as to sense a property of the target.