Microlens Array as Corrosion Barrier for Metal Optical Elements
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Solution Overview
Problem
The existing light detecting devices suffer from photomixing due to the higher layer height on the light receiving surface side of the polarization units, which causes light to be incident on neighboring pixels, leading to color mixing.
Innovation Solution
A light detecting device is designed with a microlens array that covers the light receiving surfaces of optical elements, which are made of metal, serving as both a protection film to prevent corrosion and reducing the layer height to minimize photomixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protection film is laminated on the light receiving surface side of the polarization units to suppress corrosion, then the corrosion resistance of the metal optical elements is improved, but the layer height increases and causes photomixing between neighboring pixels
Solution Approach 1:
The patent merges the protection film function with the microlens array by making the microlens array itself serve as the protection film. The microlens array is formed in direct contact with the light receiving surface of the polarization units, eliminating the need for a separate protection film layer while still providing corrosion protection to the metal optical elements.
Solution Approach 2:
The microlens array is given dual functionality: it performs its primary function of focusing and guiding incident light to the photoelectric conversion units, while simultaneously serving as a protection film that suppresses corrosion of the metal polarization units. This multi-functionality eliminates the need for additional protective layers.
2Reliability
If the layer height on the light receiving surface side is increased to accommodate a protection film, then the corrosion protection is improved, but light from one pixel can diagonally travel to neighboring pixels causing color mixing
Solution Approach 1:
The protection function is merged into the microlens array structure itself. By making the microlens array form directly on the light receiving surface of the polarization units, the design eliminates additional protective layers that would increase height and cause diagonal light travel to neighboring pixels, thereby preventing color mixing while still providing corrosion protection.
3Reliability
If a separate protection film is added to protect the polarization units, then the corrosion resistance is improved, but the device complexity and number of laminated layers increase
Solution Approach 1:
The microlens array is designed to perform multiple functions simultaneously: light focusing/guiding and corrosion protection. By making the microlens array itself serve as the protection film, the patent reduces the total number of layers and simplifies the device structure while maintaining effective corrosion suppression of the metal optical elements.
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 solution effectively suppresses corrosion of the metal optical elements and reduces photomixing by maintaining a lower layer height, thereby improving the accuracy and reliability of the light detecting device.
Implementation Method 1
a microlens array that is disposed on a light receiving surface side of the plurality of optical elements, and includes a plurality of microlenses that guide incident light to the photoelectric conversion units
Implementation Method 2
a surface on an optical element side of the microlens array is formed in contact with light receiving surfaces of the optical elements so as to cover the light receiving surfaces and also serve as a protection film that suppresses corrosion of the metal material
Data Source
AI summary
There is provided a light detecting device that can suppress corrosion of optical elements while suppressing upper layer color mixing. The light detecting device includes: a substrate on which a plurality of photoelectric conversion units are formed; a plurality of optical elements that are disposed on a rear surface side of the substrate; and a microlens array that is disposed on a rear surface side of the plurality of optical elements, and includes a plurality of microlenses. Furthermore, the optical element contains a metal material, and a surface on an optical element side of the microlens array is formed in contact with the rear surfaces of the optical elements so as to cover the rear surfaces and also serve as a protection film that suppresses corrosion of the metal material of the optical elements.