Optical Image Recognition Device Thickness Reduction via Sensor Embedding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional optical fingerprint recognition devices are too thick for modern smartphones, exceeding the 400 μm thickness requirement due to the structure of CMOS sensors, optical collimators, and IR-Cut filters, making them unsuitable for thinner mobile phone designs.
Innovation Solution
The solution involves forming a recess on a flexible printed circuit board, embedding an image sensor within it, and using a thermal release film to remove the substrate, along with an optical collimator, supporting ring, sealant, and optical filter to reduce the overall thickness of the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a conventional optical fingerprint recognition device is manufactured with CMOS sensor, optical collimator, and IR-Cut filter stacked structure, then the optical recognition function is achieved, but the total thickness reaches 475 μm which exceeds the 400 μm requirement for modern smartphones
Solution Approach 1:
The patent transitions from a conventional stacked structure to a planar integrated structure where the image sensor, optical collimator, and optical filter are arranged side-by-side on the same substrate plane. This dimensional reorganization eliminates the need for vertical stacking, reducing the thickness from 475 μm to under 400 μm while preserving all optical recognition functions through spatial redistribution of components.
2Length of moving object
If the device thickness is reduced to meet smartphone requirements, then the form factor compatibility is improved, but the structural complexity increases due to integration of multiple components on a single substrate
Solution Approach 1:
The patent merges the image sensor, optical collimator, optical filter, and circuit board into a single integrated structure where multiple functional components are combined on one substrate. The circuit board serves as both the mounting platform and structural support, while the optical components are directly integrated onto the substrate, eliminating the need for separate stacked layers and reducing overall device thickness.
Solution Approach 2:
The circuit board is designed to serve multiple functions simultaneously: it acts as the structural substrate, provides electrical connections, supports the image sensor, and integrates the optical collimator and filter. This multi-functionality reduces the need for additional supporting structures, thereby reducing overall device thickness while maintaining structural integrity.
3Length of moving object
If multiple optical components are integrated on a single substrate, then the total thickness is reduced, but the manufacturing precision requirements increase due to alignment and integration challenges
Solution Approach 1:
The patent employs preliminary action by pre-positioning the image sensor, optical collimator, and optical filter onto the circuit board substrate before final assembly. The components are arranged and fixed in their precise positions on the substrate, ensuring proper alignment is established early in the manufacturing process. This preliminary positioning simplifies subsequent assembly steps and reduces the need for complex real-time alignment adjustments.
Data Source
AI summary
An optical image recognition device and a method for fabricating the same are disclosed. The device includes a flexible printed circuit board, an image sensor, a glue, an optical collimator, a supporting ring, a sealant, and an optical filter. The top of the flexible printed circuit board is provided with a recess, the image sensor is located in the recess, the sidewalls of the image sensor and the recess are separated from each other, and the image sensor is coupled to the flexible printed circuit board through conductive wires. The glue adheres to the flexible printed circuit board and the image sensor and covers the conductive wires. The optical collimator is disposed on the image sensor. The supporting ring, disposed on the flexible printed circuit board, surrounds the glue and the optical collimator. The optical filter, disposed on the sealant, shields the optical collimator and the image sensor.