Wafer-Level Stacked Lens Unit with Corner-Notched Aperture
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing lens units for endoscopes have a large diameter, making them invasive, and current wafer-level stacked bodies face manufacturing challenges due to high residual stress and adhesive layer issues.
Innovation Solution
A lens unit design featuring a first glass substrate with a resin lens, a second glass substrate with a metal aperture layer, and an adhesive layer that does not sandwich the aperture layer's corner regions, facilitating easier manufacturing and reducing residual stress through a wafer-level stacked structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a conventional lens unit design is used, then the lens unit can be manufactured, but the diameter is large causing invasiveness in endoscope applications
Solution Approach 1:
The lens unit is divided into multiple optical devices (first optical device with resin lens, second optical device with aperture layer) that are stacked and bonded together. This segmentation allows each component to be optimized independently while achieving a compact overall diameter suitable for endoscope applications.
Solution Approach 2:
The patent transitions from a conventional planar lens arrangement to a three-dimensional stacked configuration. Multiple optical devices are arranged in the vertical dimension (optical axis direction) rather than expanding horizontally, thereby reducing the diameter while maintaining optical functionality.
2Productivity
If wafer-level stacked body manufacturing is used, then manufacturing efficiency is improved, but residual stress and adhesive layer issues arise
Solution Approach 1:
The adhesive layer configuration is optimized locally by creating corner regions where the adhesive does not sandwich the aperture layer. This local modification reduces residual stress concentration at critical points while maintaining overall manufacturing efficiency of the stacked structure.
Solution Approach 2:
The patent modifies the adhesive layer parameters by varying its presence and configuration in different regions (sandwiching in most areas, non-sandwiching in corner regions). This parameter change optimizes both the bonding strength and stress distribution in the stacked optical devices.
3Strength
If the adhesive layer sandwiches the aperture layer in all regions, then bonding strength is maximized, but residual stress increases reducing reliability
Solution Approach 1:
The adhesive layer is configured with different local properties: in most regions it sandwiches the aperture layer to provide strong bonding, while in corner regions it does not sandwich the aperture layer to reduce residual stress. This spatial variation in adhesive configuration optimizes both strength and reliability.
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 design results in a smaller, more reliable lens unit that is easier to manufacture and reduces invasiveness, while maintaining high adhesion strength and optical performance.
Implementation Method 1
an adhesive layer that adhesively bonds the first optical device and the second optical device
Data Source
AI summary
A lens unit includes: a first optical device including a first glass substrate including a first principal surface and a second principal surface, and a resin lens disposed on the second principal surface; a second optical device including a second glass substrate including a third principal surface and a fourth principal surface, in which the third principal surface is disposed facing the second principal surface, and a substantially rectangular aperture layer made of metal that is disposed on the third principal surface and that has four corner regions cut out; and an adhesive layer that adhesively bonds the first optical device and the second optical device, in which four corner regions do not sandwich the aperture layer between the first optical device and the second optical device.