Artificial Ommatidia Unit for Image Sensor Vignetting Reduction
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Solution Overview
Problem
Image sensing apparatuses face issues with light distribution, leading to vignetting and image quality deterioration due to the mismatch between the curved focal plane of imaging optical systems and the flat sensing surface of image sensors, which existing complex imaging optical systems fail to adequately address.
Innovation Solution
The implementation of an image sensing apparatus with artificial ommatidia, featuring a concave focal plane imaging optical lens group, a micro lens array on a curved top surface, and waveguides that guide light from the micro lenses to a flat image sensor, ensuring even light distribution and preventing vignetting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a complex imaging optical system with multiple aspherical lenses is used, then image focusing on the flat sensor is improved, but device complexity increases and vignetting is not fully prevented
Solution Approach 1:
The imaging optical system is divided into multiple lens groups (first lens group G1, second lens group G2, third lens group G3) with specific functions. The first lens group handles initial light convergence, the second handles focusing, and the third corrects aberrations. This segmentation allows each group to be optimized for its specific function, achieving good image quality while keeping individual lens complexity manageable.
Solution Approach 2:
Each lens group has specific local optical properties tailored to its function. The first lens group has positive refractive power for convergence, the second has specific aspherical surfaces for focusing, and the third has properties for aberration correction. This local optimization of optical quality in different regions of the system achieves overall system performance without requiring all lenses to be complex aspherical elements.
2Illumination intensity
If pixels at the circumference of the image sensor are moved to increase light reception, then light amount at circumference is improved, but interval between pixels must be increased
Solution Approach 1:
The patent employs aspherical lens surfaces with specific curvature profiles designed to redirect light rays. The aspherical surfaces have varying curvature radii that bend light paths to ensure that even oblique light rays reaching the sensor circumference are properly focused, increasing effective light amount without requiring physical pixel relocation or increased spacing.
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 collection at the image sensor's circumference, reducing vignetting and image distortion, allowing for improved image quality with a simpler lens configuration, potentially requiring only one or two lenses instead of multiple complex lenses.
Implementation Method 1
Each of the plurality of artificial ommatidia of the artificial ommatidia unit includes a micro lens disposed on the top surface of the artificial ommatidia unit; and a waveguide disposed under the micro lens to transmit the light entering the micro lens
Implementation Method 2
a waveguide disposed under the micro lens to transmit the light entering the micro lens
Data Source
AI summary
An image sensing apparatus with artificial ommatidia includes an imaging optical lens group forming a concave focal surface, an artificial ommatidia unit having a curved top surface corresponding to the concave focal surface and a flat bottom surface, and an image sensor disposed under the artificial ommatidia unit. The artificial ommatidia unit is disposed under the imaging optical lens group so that the curved top surface is coincided with the concave focal surface of the imaging optical lens group. The artificial ommatidia unit having a plurality of artificial ommatidia collects light emitting from the imaging optical lens group, and guides the light to the bottom surface thereof.