Composite Lens Layout for Temperature-Stable Vehicle Imaging
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Solution Overview
Problem
Surveillance cameras in vehicles face challenges in maintaining consistent optical performance across varying ambient temperatures, especially with the demand for high-resolution imaging for self-driving functions.
Innovation Solution
An optical imaging system comprising specific configurations of lenses made from glass and plastic materials, with refractive powers and surface shapes optimized to maintain constant optical performance across temperature changes, including a stop placement and filter to block infrared light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If lenses are made of plastic material to reduce cost and weight, then manufacturing cost and device weight are reduced, but optical performance stability under temperature changes deteriorates
Solution Approach 1:
The patent uses a composite lens structure where the lens includes a plastic lens body with a glass coating layer applied to at least one surface. This combines the cost and weight advantages of plastic with the thermal stability of glass, resolving the contradiction between ease of manufacture and reliability under temperature changes.
Solution Approach 2:
The patent specifies that the glass coating layer should have a refractive index within a specific range (1.5 to 2.0) and a thickness within a specific range (10-50 micrometers). By controlling these parameters, the lens maintains optimal optical performance while compensating for the thermal expansion characteristics of plastic material.
2Reliability
If more glass lenses are used to improve optical performance stability, then temperature resistance is improved, but manufacturing cost increases
Solution Approach 1:
Instead of using entirely glass lenses which would be costly and heavy, the patent applies glass coating layers (10-50 micrometers thick) on plastic lens bodies. This provides the thermal stability of glass with the cost and weight advantages of plastic, resolving the contradiction between temperature resistance and manufacturing cost.
3Measurement precision
If focal length is increased to improve imaging resolution, then image clarity is improved, but field of view decreases
Solution Approach 1:
The patent divides the imaging system into multiple lens units with different functions: a first lens unit for wide-angle light collection, a second lens unit for intermediate focusing, and a third lens unit for final image formation. This segmentation allows the system to achieve both high resolution and wide field of view by coordinating the functions of individual lens units.
Solution Approach 2:
The patent employs an asymmetric lens configuration where lens elements are positioned at different distances from the imaging plane and have varying aperture sizes. This dimensional variation allows light rays from different angles to be properly focused, maintaining wide field of view while achieving high resolution through the optimized spatial arrangement of lens units.
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
The system provides high-resolution imaging with minimal focal length variation and wide field of view, ensuring clear images in varying temperatures, suitable for vehicle installations.
Implementation Method 1
one of the lenses is made of a glass material... capable of implementing constant optical performance irrespective of changes in ambient temperature
Implementation Method 2
four or more of the lenses are made of a plastic material... irrespective of changes in ambient temperature
Data Source
AI summary
An optical imaging system including a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens disposed in order from an object side, wherein one or more of the first to sixth lenses is disposed between a stop and an imaging plane and of those, one or more has positive refractive power and one is made of a glass material, and four or more of the first to sixth lenses are made of a plastic material.