LIDAR Sensor Optical Element Annular Beam Eye Safety
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Solution Overview
Problem
Existing LIDAR sensor devices face challenges in achieving optimal eye safety, reducing aberrations, and minimizing installation space while maintaining effective imaging, particularly due to limitations in the design of transmitting and receiving light paths.
Innovation Solution
The sensor device employs an optical element with a cross-section surface that overlaps with an inner area not receiving light, allowing for annular or elliptical ring-shaped light emission, which enhances eye safety and flexibility, and includes a spatial mode converter to adapt light modes, such as Hermite-Gaussian or Laguerre-Gaussian modes, for improved beam management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a large lens is used to expand the light beam, then eye safety is improved, but the transmitted light beam cannot be expanded up to the maximum lens diameter and collimated at the same time
Solution Approach 1:
The light beam cross-section is segmented into an inner area and an outer annular area. The optical element is positioned such that its cross-section overlaps with the inner area, allowing the outer annular area to be expanded and collimated independently, achieving eye safety without compromising beam control capability.
Solution Approach 2:
The solution transitions from a uniform circular beam to an annular beam structure by utilizing the radial dimension. The optical element creates a beam with different properties in the radial direction (inner non-illuminated area) versus the angular direction (outer illuminated annular area), enabling simultaneous expansion and collimation.
2Object-affected harmful factors
If the light beam is expanded to maximize lens diameter, then eye safety is improved, but the installation space is increased
Solution Approach 1:
Different regions of the beam cross-section are given different qualities: the inner area is non-illuminated while the outer annular area is illuminated. This local differentiation allows the beam to maintain a compact overall size for space efficiency while the outer annular region provides sufficient expansion for eye safety.
3Reliability
If a perforated mirror is used for optical isolation, then transmit and receive paths are separated, but light losses increase
Solution Approach 1:
The optical element serves dual functions: it acts as a beam expander for the transmit path and as a beam compressor for the receive path. By merging these functions into a single element positioned in the shared part of the paths, the system achieves optical isolation without the light losses associated with separate perforated mirror components.
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 significantly enhances eye safety, reduces aberrations, and minimizes installation space by ensuring that the full power of emitted light does not incident on the retina and allows for flexible illumination patterns, leading to improved imaging and reduced installation requirements.
Implementation Method 1
an optical element being situated in a shared part of the transmit and receive paths, in such a way that the cross-section surface of the optical element in the plane perpendicular to the transmit path essentially completely overlaps with its cross-section surface the inner area to which light is not applied
Implementation Method 2
If this light is incident on a movable or fixed obstacle, for example, a moving or stationary automobile, pedestrian, or the like, it is partially reflected back in the direction of the receiving unit
Implementation Method 3
The transmitting unit emits continuous (continuous wave) or pulsed, for example, infrared laser light
Implementation Method 4
a transmitter unit having one or two optical radiation sources, which emit a diffraction-limited, visible radiation
Implementation Method 5
If one evaluates the time difference of transmit and receive points in time in a detector, the so-called TOF (time-of-flight), the path covered by the photons may be inferred via the propagation time and finally a distance to an object may be determined
Data Source
AI summary
A sensor device for detecting an object with the aid of light of at least one wavelength, including a transmitting unit for emitting light using at least one light source and a receiving unit for receiving light, the light emitted by the transmitting unit in the plane perpendicular to the transmit path having the form of a circumferential surface, which includes an inner area to which light is not applied, an optical element being situated in a shared part of the transmit and receive paths, in such a way that the cross-section surface of the optical element in the plane perpendicular to the transmit path essentially completely overlaps with its cross-section surface the inner area to which light is not applied.