Optical Module Sensor Flip-Chip Ghost Image Suppression
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Solution Overview
Problem
Conventional optical modules suffer from ghost image issues due to light reflection at the substrate end face, which enters the sensor and causes noise and image abnormalities.
Innovation Solution
The optical module design features a sensor and memory chip with different sizes, where the sensor is placed above the memory chip, and they are connected via flip-chip and wire bonding, with the sensor projecting into the substrate opening to reduce light reflection and ghosting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the sensor is flip-chip connected to the substrate, then the module size is reduced, but light reflection at the substrate end face causes ghost images
Solution Approach 1:
A black matrix layer is introduced as an intermediary substance between the sensor and the substrate end face. This black matrix absorbs reflected light before it can re-enter the sensor, thereby eliminating ghost images while preserving the compact flip-chip connection structure
Solution Approach 2:
The harmful reflected light is extracted from the optical path by using the black matrix to absorb it at the substrate end face, removing the ghost image problem without changing the fundamental flip-chip connection architecture
2Device complexity
If the sensor and memory chip have the same size, then the structure is simplified, but the sensor may be damaged during flip-chip connection
Solution Approach 1:
The sensor is designed with an asymmetric size relationship to the memory chip, making the sensor slightly smaller. This asymmetric configuration prevents the sensor from protruding during flip-chip connection, eliminating the risk of mechanical damage while maintaining structural simplicity
Solution Approach 2:
The size difference between sensor and memory chip serves as a preventive measure before connection occurs, ensuring the sensor does not protrude and get damaged during the flip-chip bonding process
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 effectively suppresses ghost images by minimizing light reflection, enhancing image quality and reducing the likelihood of damage during the flip-chip connection process.
Implementation Method 1
a sensor (110) configured to pick up an image of an image pickup object
Implementation Method 2
The memory chip (122) is flip-chip connected through bumps (113) to a substrate (114)
Data Source
AI summary
The present optical module includes a sensor configured to pick up an image of an image pickup object, and a memory chip configured to store pixel data read out from the sensor and having the sensor joined thereto. The memory chip is connected to a substrate by a connection portion by flip-chip connection. The sensor can be connected by a wire to the memory chip, to which the sensor is joined. Further, the sensor can be joined to the memory chip in such a manner as to project toward an opening of the substrate. The present technology can be applied to a camera module.