Offset LED Illumination for Uniform Near-Far Field Imaging
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Solution Overview
Problem
Existing 2-D imaging systems face challenges in maintaining uniform illumination over a wide range of distances due to the narrow depth of field, leading to suboptimal solutions that are either large, expensive, or cumbersome, and often position illumination sources in a way that can shine into users' eyes.
Innovation Solution
A plurality of LEDs are positioned behind lenses in an offset manner, with a masking device to direct illumination to both near and far fields of view while shielding users from direct light, allowing for selective or automatic activation based on distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If additional LEDs are installed to illuminate the near field, then illumination uniformity is improved, but device size and manufacturing cost increase
Solution Approach 1:
The patent repositions the LED from a vertical orientation to a horizontal orientation behind the imaging array. This dimensional change allows the light to travel through the housing structure and illuminate the near field uniformly without requiring additional vertical space or multiple LED layers, thus maintaining illumination uniformity while reducing device size complexity
Solution Approach 2:
The single horizontally-oriented LED serves dual purposes: it provides illumination for both the near field and far field by strategically positioning the LED behind the imaging array and utilizing the housing structure as a light guide, eliminating the need for separate near-field and far-field illumination systems
2Illumination intensity
If additional LEDs are installed to illuminate the near field, then illumination uniformity is improved, but manufacturing cost increases
Solution Approach 1:
The single horizontally-oriented LED serves dual purposes: it provides illumination for both the near field and far field by strategically positioning the LED behind the imaging array and utilizing the housing structure as a light guide, eliminating the need for separate near-field and far-field illumination systems, thereby reducing component count and manufacturing cost
Solution Approach 2:
The patent merges the near-field illumination function and far-field illumination function into a single LED system. By combining these functions and using the existing housing structure as part of the illumination path, the design reduces the number of components that need to be manufactured and assembled, lowering overall manufacturing cost
3Illumination intensity
If illumination sources are positioned to illuminate near field, then near field illumination is improved, but user eye safety deteriorates
Solution Approach 1:
The patent employs asymmetric positioning of the LED horizontally behind the imaging array, oriented at an angle rather than directly facing the lens. This asymmetric arrangement directs illumination toward the near field while angling the light path away from the user's line of sight, thereby providing effective near-field illumination while minimizing direct light exposure to user eyes
Solution Approach 2:
The housing structure serves as an intermediary element that guides and redirects light from the horizontally-oriented LED. The light travels through the housing to reach the near field illumination target, while the housing geometry prevents direct line-of-sight exposure to the user, effectively mediating between the illumination requirement and eye safety concern
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 provides uniform illumination from near to far fields of view, reducing manufacturing costs and avoiding eye exposure, while allowing for flexible operation modes.
Implementation Method 1
A plurality of illumination sources such as LEDs are utilized, where each is positioned behind a lens in an offset manner
Implementation Method 2
each is positioned behind a lens in an offset manner so that the lens acts to direct the illumination
Data Source
AI summary
An imaging device preferably for use in a 2-D CCD or CMOS sensor is disclosed. The illumination means uses a plurality of illumination sources, some of which are coupled to lenses in an offset manner to promote far field illumination, and some of which are not so coupled and are arranged to provide near field illumination.