Image Sensor Reflectors Extend Optical Path
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Solution Overview
Problem
Image sensing devices face challenges in efficiently sensing infrared light without increasing the thickness of the substrate, which leads to reduced photoelectric conversion efficiency and increased production costs.
Innovation Solution
Incorporating a first reflector and a second reflector to extend the optical path of incident light, allowing it to penetrate deeper into the substrate, thereby enhancing photoelectric conversion efficiency without the need for a thicker substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the substrate thickness is increased to improve infrared light sensing, then photoelectric conversion efficiency is improved, but device size and production cost increase
Solution Approach 1:
The patent introduces reflectors that redirect light laterally through the substrate, transforming the light propagation path from a simple vertical transmission to a multi-dimensional zigzag path. This allows the optical path length to exceed the substrate thickness, improving infrared sensing efficiency without increasing the physical thickness of the substrate.
Solution Approach 2:
The patent employs reflective surfaces (including curved or angled reflectors) that bend and redirect light paths through the substrate. This curvature-based light redirection creates extended optical paths within the constrained substrate thickness, enabling improved photoelectric conversion for infrared wavelengths without increasing device dimensions.
2Measurement precision
If conventional light sensing methods are used, then device structure is simple, but infrared light sensing efficiency is insufficient
Solution Approach 1:
The patent divides the light sensing function into multiple stages by introducing separate reflector components (first reflector, second reflector) that work in sequence. Each reflector segment handles a specific portion of the light redirection task, collectively achieving extended optical path length and improved infrared sensing without requiring complete structural redesign.
Solution Approach 2:
The patent introduces reflectors as intermediary elements between the incident light and the photoelectric conversion layer. These intermediaries redirect and extend the light path through the substrate, enabling improved infrared sensing efficiency without directly modifying the photoelectric conversion elements or requiring thicker substrates.
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 significantly increases the optical path length of infrared light, improving sensitivity and photoelectric conversion efficiency while maintaining a minimal device size and reducing production costs.
Implementation Method 1
a first reflector located to spatially overlap with a portion of the photoelectric conversion element to receive light and configured to reflect the light incident to the photoelectric conversion element in a direction away from the photoelectric conversion element
Implementation Method 2
a second reflector disposed to be spaced from the first reflector and configured to reflect the light reflected by the first reflector back towards the photoelectric conversion element
Implementation Method 3
a microlens configured to converge the light upon the photoelectric conversion element
Implementation Method 4
a substrate structured to support a photoelectric conversion element which generates photocharges in response to light incident to the photoelectric conversion element
Data Source
AI summary
An image sensing device includes a substrate, a first reflector, and at least one second reflector. The substrate includes a photoelectric conversion element corresponding to each unit pixel. The first reflector is disposed in a manner that at least some parts of the first reflector overlap with the photoelectric conversion element, and is configured to reflect incident light directed to the photoelectric conversion element in a direction away from the photoelectric conversion element. The second reflect disposed over the substrate is configured to reflect the incident light reflected by the first reflector in a direction along which the incident light moves again closer to the photoelectric conversion element.