Imaging Device Light-Shielding Layer Segmentation
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Solution Overview
Problem
Solid-state imaging devices using organic photoelectric conversion films face challenges with light-shielding films causing stress-induced peeling and optical property deterioration due to thick buffer layers and light-shielding films positioned above the organic layer, leading to issues like color mixture, vignetting, and flare ghost.
Innovation Solution
An imaging device design featuring a black layer on an electrically-conducive light-shielding layer that extends from the pixel region to the surrounding region, reducing the thickness of the light-shielding layer and buffer layer, thereby alleviating stress and improving optical properties by attenuating light input and reducing reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a thick light-shielding film is formed to improve light-shielding performance, then light-shielding performance is improved, but stress-induced peeling of the organic photoelectric conversion film occurs
Solution Approach 1:
The light-shielding function is divided into two separate layers: an electrically-conductive layer providing light-shielding properties and a black layer provided on top of it. This segmentation allows the electrically-conductive layer to be thinner (reducing stress) while the black layer enhances light-shielding performance, resolving the contradiction between light-shielding effectiveness and stress-induced peeling.
2Reliability
If a thick buffer layer is provided to protect the organic photoelectric conversion film, then adhesion and protection are improved, but optical properties deteriorate due to color mixture and vignetting
Solution Approach 1:
The protective and light-shielding functions are segmented into multiple thin layers (electrically-conductive layer and black layer) rather than using a single thick buffer layer. This allows adequate protection while maintaining optical properties by reducing the total thickness and eliminating the color mixture and vignetting issues caused by thick buffer layers.
3Object-affected harmful factors
If a metal light-shielding film is disposed on a layer higher than the organic photoelectric conversion film, then light-shielding performance is improved, but flare ghost occurs due to reflection
Solution Approach 1:
The potentially harmful reflection from the light-shielding structure is converted into a beneficial effect by stacking the black layer on the electrically-conductive layer. The black layer absorbs reflected light, preventing flare ghost while maintaining the light-shielding performance of the electrically-conductive layer.
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 reduces the thickness of the light-shielding and buffer layers, minimizing stress-induced peeling and optical property deterioration, enhancing imaging quality by reducing color mixture and flare ghost occurrences.
Implementation Method 1
The electrically-conducive layer has a light-shielding property
Implementation Method 2
there is a possibility that flare ghost occurs due to reflection from a metal light-shielding film
Data Source
AI summary
An imaging device according to an embodiment of the present disclosure includes: a pixel region in which a plurality of pixels is disposed; a surrounding region provided around the pixel region; an organic photoelectric conversion layer continuously provided from the pixel region to a portion of the surrounding region; an electrically-conducive layer provided on the organic photoelectric conversion layer from a periphery of the pixel region to the surrounding region; and a black layer provided on the electrically-conducive layer. The electrically-conducive layer has a light-shielding property.