Lens Assembly Embedded Filter for Ambient Light Interference
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Solution Overview
Problem
Imaging devices used in augmented and virtual reality systems face challenges in producing quality images due to interference from background ambient light, which existing technologies struggle to efficiently filter, especially when light is incident at angles outside the designed range for filtering elements.
Innovation Solution
The integration of a filtering element within the lens assembly of the imaging device, positioned to receive light within a specific range of angles, ensures efficient filtering by maintaining the desired passband and blocking undesired light components, even when light is incident at angles deviating from normal incidence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a filtering element is placed in the imaging device to block undesired light components, then light filtering effectiveness is improved, but device complexity increases
Solution Approach 1:
The filtering element is integrated within the lens assembly structure, merging the filtering function with the existing optical assembly. This combination allows the filter to be positioned at an optimal location within the lens assembly where it can effectively block ambient light interference while utilizing the existing mechanical structure, thereby avoiding significant increases in overall device complexity
Solution Approach 2:
The lens assembly serves multiple functions: it focuses light onto the detector and simultaneously houses the filtering element that blocks undesired light components. By making the lens assembly a multi-functional component that incorporates both optical focusing and light filtering capabilities, the design reduces the need for separate dedicated filtering structures, thus managing device complexity while improving filtering effectiveness
2Adaptability or versatility
If the filtering element is positioned to receive light at various angles, then adaptability to different lighting conditions is improved, but manufacturing precision requirements increase
Solution Approach 1:
The filtering element is positioned at a specific location within the lens assembly where the optical path naturally directs light at controlled angles. By selecting a positioning location that inherently receives light within the desired angular range, the design achieves adaptability to different lighting conditions while avoiding the need for extremely precise manufacturing tolerances, as the optical geometry itself provides angular control
Solution Approach 2:
The filtering element is oriented and positioned to receive light within a range of angles that maintains effective filtering performance. By designing the filter's angular acceptance range to match the angular distribution of light at its position within the lens assembly, the system creates an equipotential condition where filtering effectiveness is maintained across varying incident angles without requiring ultra-precise positioning
3Measurement precision
If the filtering element blocks specific light bands, then measurement precision is improved, but loss of useful light increases
Solution Approach 1:
The filtering element is designed with specific spectral transmission characteristics that allow it to block undesired light bands (such as ambient light frequencies) while transmitting the wavelength range corresponding to the projected light used for depth sensing. By carefully selecting the filter's spectral parameters, the system achieves improved measurement precision through better signal-to-noise ratio while minimizing loss of the useful light signal
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 effectively filters ambient light and maintains image quality by ensuring the filtering element operates within its designed range, reducing interference and enhancing depth sensing capabilities in both indoor and outdoor environments.
Implementation Method 1
The filtering element may be configured to reduce an intensity of a portion of the collimated light to generate the filtered light
Data Source
AI summary
An imaging device for imaging of a local area surrounding the imaging device. The imaging device includes a lens assembly, a filtering element and a detector. The lens assembly is configured to receive light from a local area surrounding the imaging device and to direct at least a portion of the received light to the detector. The filtering element is placed in the imaging device within the lens assembly such that light is incident at a surface of the filtering element within a range of angles determined by a design range of angles at which the filtering element is designed to filter light. The detector is configured to capture image(s) of the local area including the filtered light. The imaging device can be integrated into a depth camera assembly for determining depth information of object(s) in the local area based on the captured image(s).