Offset Diaphragms in Microlens Arrays for Ghost Image Suppression
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Solution Overview
Problem
Conventional image acquisition systems face limitations in angular resolution and field of view due to crosstalk issues leading to ghost images, which are costly to resolve with high-tech production methods and complex optical isolation techniques, and struggle to maintain image quality across a large field of view.
Innovation Solution
The introduction of offset diaphragms between microlenses and detectors, allowing specific angles of incidence to be focused while blocking others, eliminates crosstalk and enables a larger scannable field of view without the need for partition walls, using adaptable aperture arrays and varied lens designs for aberration correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If absorbent partition walls are used between channels to prevent crosstalk, then ghost images are suppressed, but device complexity and manufacturing cost increase significantly
Solution Approach 1:
The patent divides the optical system into discrete channels, each with its own microlens, aperture diaphragm, and detector. This segmentation allows independent optimization of each channel while maintaining overall system performance, eliminating the need for complex partition walls between channels.
Solution Approach 2:
The patent applies local quality by providing each optical channel with specifically tailored components - individual aperture diaphragms positioned at optimized locations for each channel, and detectors with active areas matched to the specific light cone geometry of each microlens. This local optimization achieves ghost image suppression without requiring complex global partition structures.
2Measurement precision
If the number of optical channels is increased to improve angular resolution, then measurement precision improves, but detector array area and production cost increase
Solution Approach 1:
The patent transitions from a conventional 2D detector array to a 3D optical path encoding system where spatial information is encoded in the angular distribution of light across multiple channels. Each channel captures light from a specific angular range, and the combination of channel positions and light angles provides enhanced angular resolution without requiring a proportionally larger detector area.
Solution Approach 2:
The patent changes the key parameter from detector pixel density to channel angular separation. By optimizing the angular field of view of each channel and the spacing between channels, the system achieves high angular resolution through parameter optimization rather than simply increasing the number of detectors, thereby controlling detector array area and production costs.
3Adaptability or versatility
If a large field of view is implemented, then adaptability improves, but image quality and distortion correction become more difficult
Solution Approach 1:
The patent segments the large field of view into multiple smaller angular ranges, each handled by a dedicated optical channel with its own microlens and aperture diaphragm. Each channel is optimized for its specific angular range, maintaining high image quality and minimal distortion within that range. The combination of multiple channels provides the overall large field of view with uniformly high quality across the entire viewing area.
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 the spatial-sandwidth product, resolving power, and light intensity of the imaging system, allowing for accurate position determination of point sources and edges with improved image quality across a larger field of view without increasing production complexity or costs.
Implementation Method 1
each optical channel, which is assigned a microlens, an aperture diaphragm assigned to it and a detector... light of a specific angle of incidence for which all diaphragm openings with lens and Detector lie on a straight line, is focused by a lens onto the detector assigned to it
Implementation Method 2
all other angles of incidence are blocked by the one additional aperture or by several additional apertures just before the image plane of the microlens, i.e. they are absorbed or reflected
Data Source
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AI summary
According to the invention, the image detection system contains optical channels arranged one next to the other with a respectively assigned microlens with aperture and in each case at least one detector located in the image plane, wherein the detectors are arranged such that the directions of the optical axes, which form in each case the connecting lines between lens apices and centre of the detectors, represent a function of the position of the respective optical channel, wherein at least one aperture stop arrangement (4) is provided between the microlenses (1’) with aperture (2’) and the detectors (6’, 8), wherein the distance between centres of the aperture stops (4’) is located between the distance between apices of the microlenses (1’) and distance between centres of the detectors (6’, 8) such that, depending on the position of the channels, the aperture stops (4’) are arranged with different offsets to the microlenses (1’) and the detectors (6’, 8) and are in each case located on a straight line with them.