Depth Sensor Pixel With Shared Floating Diffusion Nodes
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Solution Overview
Problem
Conventional depth sensors face reduced sensitivity and precision in distance calculation due to increased pixel distance and reduced photoelectric charge transmission speed, leading to incorrect distance measurement between the sensor and target objects.
Innovation Solution
A unit pixel design for depth sensors incorporating a light-intensity output circuit and shared first and second light-intensity extraction circuits, which generate and transmit electric charges corresponding to reflected light, with shared floating diffusion and drain nodes between adjacent pixels to minimize space and enhance transmission speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If each pixel has an independently constructed floating diffusion node or drain node, then the pixel structure is complete and functional, but the distance between pixels increases resulting in reduced sensitivity and decreased charge transmission speed
Solution Approach 1:
Adjacent pixels share common floating diffusion nodes and drain nodes, merging previously independent structures into shared resources. This reduces the distance between pixels and increases the number of photoelectric conversion devices per unit area, thereby improving sensitivity and distance measurement precision without compromising pixel functionality
Solution Approach 2:
The shared floating diffusion nodes and drain nodes serve multiple pixels simultaneously, allowing a single structure to perform the function of charge collection and signal generation for multiple photoelectric conversion devices. This multi-functional approach increases device density while maintaining operational reliability
2Measurement precision
If the distance between pixels is reduced to improve sensitivity and transmission speed, then sensitivity and precision improve, but the space requirements decrease making layout more difficult
Solution Approach 1:
By merging the floating diffusion nodes and drain nodes into shared structures between adjacent pixels, the patent reduces the overall space required per pixel. This allows pixels to be positioned closer together, improving sensitivity and distance calculation precision while the shared structures manage the layout complexity through standardized interconnections
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 design improves the sensitivity and precision of depth sensors by minimizing space and increasing the speed of electric charge transmission, resulting in accurate distance calculations and enhanced sensitivity.
Implementation Method 1
Each of the photoelectric conversion devices may generate photoelectric charges according to the amount of the pulse light reflected from the light source and returning back to the depth sensor
Data Source
AI summary
A unit pixel of a depth sensor including a light-intensity output circuit configured to output a pixel signal according to a control signal, the pixel signal corresponding to a first electric charge and a second electric charge, a first light-intensity extraction circuit configured to generate the first electric charge and transmit the first electric charge to the light-intensity output circuit, the first electric charge varying according to an amount of light reflected from a target object and a second light-intensity extraction circuit configured to generate the second electric charge and transmit the second electric charge to the light-intensity output circuit, the second electric charge varying according to the amount of reflected light. The light-intensity output circuit includes a first floating diffusion node. Accordingly, it is possible to minimize waste of a space, thereby manufacturing a small-sized pixel.