Photodiode Lens Stack With Buffer Layer for Stable Light Focusing
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Solution Overview
Problem
Variations in the shape of lenses in detection devices can reduce detection accuracy due to inconsistent light focusing on photodiodes, necessitating a solution to stabilize lens placement and shape.
Innovation Solution
A detection device is designed with a substrate, photodiode, lens, light-blocking layer, and light-transmitting resin and buffer layers, where the lens is in direct contact with the buffer layer, and the light-blocking layer has openings to accurately position the lens over the photodiode, improving light focusing and reducing lens separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If lenses are provided directly on top of the light-transmitting resin layer, then device complexity is reduced, but lens shape variations increase which reduces detection accuracy
Solution Approach 1:
A buffer layer is introduced as an intermediary between the light-transmitting resin layer and the lens. This buffer layer acts as a mediator that stabilizes the lens shape and position without adding complex structural elements. The buffer layer compensates for variations in the underlying resin layer, ensuring consistent lens formation and maintaining detection accuracy while keeping the overall structure relatively simple.
Solution Approach 2:
The buffer layer is formed in advance before the lens is created, preliminarily establishing a stable foundation that prevents shape variations. By preparing the buffer layer beforehand with appropriate material properties and thickness, the system pre-establishes conditions that will maintain lens shape consistency during subsequent lens formation processes.
2Ease of manufacture
If lenses are placed directly on the light-transmitting resin layer, then ease of manufacture is improved, but lens position stability deteriorates leading to reduced detection accuracy
Solution Approach 1:
The buffer layer serves as a mediator that facilitates easy lens assembly while simultaneously ensuring position stability. It provides a controlled interface between the resin layer and lens, allowing for simple manufacturing processes while preventing lens displacement or misalignment that would otherwise occur with direct placement on the resin layer.
Solution Approach 2:
The buffer layer changes the physical parameters of the interface between the resin layer and lens, specifically modifying adhesion properties, mechanical support characteristics, and positional constraints. These parameter changes enable both ease of manufacture and position stability by creating optimal bonding conditions and mechanical support without complicating the assembly process.
3Device complexity
If the lens is in direct contact with the light-transmitting resin layer, then device complexity is reduced, but curvature variations increase which affects light focusing consistency
Solution Approach 1:
The buffer layer acts as an intermediary that decouples the lens curvature from variations in the underlying light-transmitting resin layer. It provides a stable reference plane that ensures consistent lens curvature formation, preventing shape variations that would otherwise be transmitted from the resin layer to the lens, thereby maintaining uniform light focusing across all photodiodes.
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 configuration enhances detection accuracy by stabilizing the lens shape and position, reducing variations in curvature and preventing lens separation, thereby improving the consistency of light focusing on photodiodes.
Implementation Method 1
a lens provided so as to overlap the photodiode... the state of light focused on the photodiodes through the lenses
Data Source
AI summary
A detection device includes a substrate, a photodiode provided on the substrate, a lens provided so as to overlap the photodiode, a light-blocking layer that is provided between the photodiode and the lens, and is provided with an opening in a region overlapping the photodiode, and a light-transmitting resin layer and a buffer layer that are stacked between the light-blocking layer and the lens. The lens is provided in direct contact with a top of the buffer layer.