Optical Imaging Lens Uniform Black Appearance via Reflectance Control
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Solution Overview
Problem
Optical imaging lenses with minimum-aperture light-shielding sheets experience color inconsistency when the inner edge radius of the light-shielding sheet is smaller than the effective radius of the lens element, making them visible and not uniformly black, especially when integrated into portable electronic devices.
Innovation Solution
The optical imaging lens design includes a front lens element group, a minimum-aperture light-shielding sheet, and a rear lens element group, with a light-absorbing layer on the non-optical effective area of the lens element and an optical film on the light-shielding sheet, optimizing reflectance ratios to achieve a uniform black appearance by ensuring the reflectance of the lens element's non-optical area is proportional to the light-shielding sheet's reflectance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inner edge radius of the minimum-aperture light-shielding sheet is made smaller to improve optical performance, then the light-shielding effectiveness is improved, but the appearance consistency deteriorates because the exposed lens surfaces show color inconsistency with the lens barrel
Solution Approach 1:
The patent applies color change principles by coating the non-optical effective areas of the lens elements with light-absorbing materials that have specific reflectance characteristics. The coating is designed to absorb light across the visible spectrum (450-750nm) to achieve a uniform black appearance that matches the lens barrel, resolving the color inconsistency issue while maintaining the small inner edge radius design
Solution Approach 2:
The patent changes the optical parameters of the exposed lens surfaces by introducing coatings with controlled reflectance properties. The coating parameters are optimized to achieve RLavg/RS0avg between 1.5-3.0, where RLavg is the average reflectance of the lens element's non-optical area and RS0avg is the reflectance of the light-shielding sheet, creating visual consistency
2Adaptability or versatility
If the inner edge radius of the minimum-aperture light-shielding sheet is made smaller to improve optical performance, then the field of view is improved, but the visible appearance inconsistency makes the lens noticeable in portable electronic devices
Solution Approach 1:
The patent converts the harmful effect of exposed lens surfaces (which normally create visible color inconsistency) into a beneficial outcome by applying light-absorbing coatings. The exposed areas that would normally be visible are instead made to match the lens barrel appearance, turning a visual defect into an aesthetic advantage for seamless integration in portable electronic devices
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 design ensures the optical imaging lens appears nearly uniformly black under illumination, allowing it to be seamlessly integrated into portable electronic devices without visible color inconsistencies.
Implementation Method 1
a light-absorbing layer disposed on the non-optical effective area of the second surface of the first lens element
Implementation Method 2
an optical film arranged on the first surface of the minimum-aperture light-shielding sheet
Data Source
AI summary
An optical imaging lens including a front lens element group, a minimum-aperture light-shielding sheet and a rear lens element group sequentially arranged along an optical axis from an object side to an image side is provided. The front lens element group includes a first lens element. The first lens element includes a first surface facing the object side and a second surface facing the image side. The first surface includes an object-side surface allowing imaging rays to pass through and a non-optical effective area. The second surface includes an image-side surface allowing imaging rays to pass through and a non-optical effective area. The optical imaging lens further includes a light-absorbing layer disposed on the non-optical effective area of the second surface and an optical film disposed on a first surface of the minimum-aperture light-shielding sheet. The optical imaging lens satisfies the conditions of 2.200≤RLavg/RS0avg and RLavg≤3.000%.