Prism-Based Bistatic LIDAR Sensor for Wide FOV
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Solution Overview
Problem
Bistatic LIDAR sensors face limitations in achieving a large in-plane field of view (FOV) and low profile due to vignetting constraints imposed by the size and position of side mirrors, which restricts their ability to detect objects at varying ranges effectively.
Innovation Solution
The use of a beam steering section with a prism positioned between the X-mirror and Y-mirror, allowing the launch and return beams to be steered without moving the optical head, and a refractive boundary that increases the FOV while maintaining a compact structure, enabling a fourfold increase in the receiving aperture and a twofold increase in operating range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If side mirrors are used in bistatic LIDAR sensors to steer beams, then beam direction control is achieved, but vignetting constraints limit the field of view and increase device size
Solution Approach 1:
The patent replaces the mechanical beam steering system using side mirrors with an optical beam steering system using a prism. The prism utilizes refraction and total internal reflection to steer both launch and return beams, eliminating the mechanical constraints and vignetting effects associated with mirror-based systems. This substitution enables a larger field of view without the limiting factors of mirror size and position.
2Area of moving object
If side mirrors are positioned to control beam paths, then beam steering is achieved, but the receiving aperture size is restricted
Solution Approach 1:
The patent replaces the mirror-based beam steering mechanism with a prism-based optical system. This substitution removes the constraints on receiving aperture size that were imposed by mirror positioning requirements. The prism can accommodate larger receiving apertures while maintaining effective beam steering through optical refraction and reflection, thereby increasing the area parameter without the corresponding device complexity of mirror alignment.
3Area of stationary object
If the optical base plate size is reduced for a low profile, then compact structure is achieved, but field of view and detection capability are limited
Solution Approach 1:
The patent utilizes the third dimension (vertical depth) within the prism to achieve beam steering that was previously requiring horizontal space. By employing refraction and total internal reflection within the prism structure, the system accomplishes beam direction control without increasing the optical base plate area, thereby maintaining a compact low-profile structure while expanding the field of view capability.
Solution Approach 2:
The replacement of mirror-based mechanical steering with prism-based optical steering enables a more compact configuration. The prism integrates multiple optical functions (beam steering, wavelength separation) in a single component that occupies less space on the optical base plate, allowing for reduced device footprint while maintaining or enhancing field of view.
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 allows for a significantly larger FOV of up to 60° and a reduced optical base plate size, enhancing the sensor's ability to detect objects at various ranges without vignetting, while maintaining a low profile and efficient operation.
Implementation Method 1
a beam steering section with a prism positioned between the X-mirror and Y-mirror, allowing the launch and return beams to be steered
Implementation Method 2
a refractive boundary that increases the FOV while maintaining a compact structure
Implementation Method 3
A pulsed launch laser beam 8 emanating from the laser source 2 passes through the first lens 3 and beam splitter 4, projecting the launch beam 8 onto an object 10
Implementation Method 4
whose range is to be measured. The beam splitter 4 receives laser light reflected back from the object 10
Implementation Method 5
The beam splitter 4 reflects the return beam 9 at 90° onto the detector 7 via the second lens 6
Data Source
AI summary
A sensor for determining a profile of an object surface relative to a reference plane includes a radiation source, a collector, a processor, first and second reflectors and at least one reflective element comprising third and fourth reflectors secured in mutual angular relation. The radiation source projects a launch beam for impingement onto the object surface. The collector detects at least a portion of a return beam reflected by the object surface. The processor determines the profile of the object surface at a point of impingement of the launch beam onto the object surface from at least one characteristic of the at least a portion of the return beam.