Optical Metaelement for 3D Light-Section Camera Sensitivity
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Solution Overview
Problem
Existing camera systems using light-section methods for 3D image data acquisition face challenges with oblique light incidence due to the Scheimpflug arrangement, leading to reduced light sensitivity and increased complexity, size, and manufacturing costs.
Innovation Solution
The integration of an optical metaelement in the receiving optics compensates for oblique light incidence by modifying the angle of incidence to perpendicular or near-perpendicular, thereby improving light sensitivity and enabling more compact designs without the need for a physical Scheimpflug arrangement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a Scheimpflug arrangement is used to record the light pattern sharply over the entire measuring range, then the image quality is improved, but the light sensitivity is reduced and the device size increases
Solution Approach 1:
The patent introduces an optical metaelement as an intermediary component between the image sensor and the incoming light. This metaelement modifies the wavefront of the obliquely incident light to compensate for the angle of incidence, allowing the Scheimpflug arrangement to maintain sharp image quality while restoring light sensitivity by ensuring proper light coupling to the sensor pixels.
Solution Approach 2:
The patent changes the optical parameters of the light propagation by using an optical metaelement to modify the wavefront. This allows the system to operate with perpendicular or near-perpendicular light incidence at the sensor, thereby improving light sensitivity while maintaining the benefits of the Scheimpflug arrangement for image quality.
2Manufacturing precision
If a Scheimpflug arrangement is used to record the light pattern sharply, then the image quality is improved, but the device complexity and size increase
Solution Approach 1:
The optical metaelement serves as a compact intermediary that enables the Scheimpflug arrangement to function effectively without requiring complex mechanical adjustments or additional optical components. The metaelement integrates the wavefront modification function into a single element, reducing overall device complexity while maintaining image quality.
3Illumination intensity
If microlenses are offset to compensate for oblique light incidence, then light sensitivity is improved, but manufacturing cost increases and custom design is required
Solution Approach 1:
The patent employs an optical metaelement that can be manufactured using standard semiconductor fabrication processes, making it a cost-effective solution compared to custom-offset microlens designs. The metaelement can be produced as a standard component that works with conventional image sensors, eliminating the need for expensive custom sensor designs.
4Device complexity
If oblique light incidence is allowed, then device design is simplified, but multiple reflections in glass cover occur and light sensitivity is reduced
Solution Approach 1:
The patent converts the harmful effect of oblique light incidence (which causes multiple reflections and reduced light sensitivity) into a beneficial situation by using the optical metaelement to modify the wavefront. The metaelement pre-corrects the light paths so that the light arrives at the sensor with the desired angle, eliminating the harmful reflections while maintaining simplified device design.
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 solution enhances light sensitivity, mitigates the disruptive effects of oblique light incidence, and allows for more compact and cost-effective camera designs, while also facilitating linearization of height resolution and multifocal image acquisition.
Implementation Method 1
The optical metaelement has a metasurface and/or a metamaterial, i.e. nanostructures that specifically form certain wavefronts of the remitted light beam
Implementation Method 2
The optical metaelement compensates for oblique light incidence on the light receiving elements. The oblique light incidence results in particular, as discussed in the introduction, from the tilt between the image plane and focal plane and/or a respective chief ray angle.
Data Source
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AI summary
A camera (10) for capturing 3D image data (20) using a light sectioning method is described. The camera comprises an illumination unit (12) for projecting a light pattern (14) onto a focal plane (28), an image sensor (22) with a plurality of light-receiving elements in an image plane, a receiving optic (26) with a lens plane arranged upstream of the image sensor (22), and a control and evaluation unit (24) configured to generate the 3D image data (20) by evaluating the light pattern (14) in an image of the image sensor (22), wherein the image plane is tilted relative to the focal plane (28). The receiving optic (26) includes at least one optical meta-element (30) that compensates for oblique light incidence onto the light-receiving elements.