Solid-State Imaging Device Pixel Memory Integration
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Solution Overview
Problem
Existing camera systems are vulnerable to image editing, rewriting, and erasure since they record images on media like memory cards or optical discs, which are easily accessible for user modifications.
Innovation Solution
A solid-state imaging device with a pixel array incorporating a photodiode, floating diffusion, transfer transistor, amplifying transistor, and a non-volatile memory section that stores images internally, allowing for a save mode where images are stored in a non-volatile manner without the need for external recording media.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If images are recorded to a recording medium such as a memory card or optical disc, then images can be accessed and stored externally, but images become vulnerable to editing, rewriting, and erasure
Solution Approach 1:
The patent extracts the image storage function from external recording media and integrates it directly into the pixel structure of the solid-state imaging device. Each pixel includes a non-volatile memory section that stores image data internally, eliminating the need for external memory cards or optical discs, thereby preventing unauthorized access and modification while maintaining storage capability
Solution Approach 2:
The patent implements a nested structure where the non-volatile memory section is embedded within each pixel unit. The memory transistor and charge storage layer are integrated into the pixel circuit, creating a hierarchical nesting where storage functionality is contained within the imaging unit itself, securing images against external tampering
2Reliability
If a non-volatile memory section is added to each pixel, then images can be stored securely without external media, but circuit complexity increases
Solution Approach 1:
The patent merges the memory storage function with the pixel circuit by integrating a memory transistor and charge storage layer directly into each pixel. This combination eliminates the need for separate external memory components and reduces overall system complexity despite adding internal storage capability, as the memory structure shares physical space and control signals with the imaging circuit
Solution Approach 2:
The pixel structure is designed to perform multiple functions: photodiode for light detection, floating diffusion for charge conversion, transfer transistor for charge transfer, amplifying transistor for signal amplification, and non-volatile memory section for secure storage. This multi-functional integration reduces the need for additional dedicated components, offsetting the complexity increase from adding memory functionality
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 enables secure, non-volatile storage of still images within the camera system, preventing external editing or erasure and reducing circuit complexity by storing images as analog data directly in the memory transistors, eliminating the need for external recording media.
Implementation Method 1
a photodiode that converts incident light into charge
Implementation Method 2
The memory transistor includes a memory gate electrode and a charge storage layer
Data Source
AI summary
The present invention provides a solid-state imaging device and a camera system capable of recording a still image without using a recording medium. Each pixel P of an image sensor is provided with a photodiode, a transfer transistor, a reset transistor, and an amplifying transistor, as well as a memory element that has functions of a select transistor. The memory element has a structure integrating a drain side select transistor, a source side select transistor, and a memory transistor. By applying a program voltage to a memory gate electrode as a gate voltage, the memory transistor stores charge of an amount corresponding to an amount of light received by the photodiode in a charge storage layer.