Distance Image Sensor Pixel Layout for Uniform TOF Output
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Solution Overview
Problem
The symmetry of pixels in existing distance image capturing elements is compromised due to the presence of control transistors, leading to non-uniform pixel output characteristics and reduced accuracy in distance measurement.
Innovation Solution
A distance image capturing element with a pixel array where each pixel includes N charge accumulation units, N transfer transistors, N reset transistors, and N control transistors, with at least one control transistor connected to a control wiring line and the rest in a non-conductive state, ensuring uniform pixel output characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If control transistors are added to pixels for charge accumulation, then charge accumulation function is improved, but pixel symmetry is compromised and output characteristics become non-uniform
Solution Approach 1:
The patent applies local quality by differentiating the connection state of control transistors across different pixels. Specifically, at least one control transistor in each pixel is connected to a control wiring line to enable charge accumulation, while other control transistors are fixed in a non-conductive state. This local differentiation allows each pixel to have the necessary charge accumulation capability while maintaining uniformity in output characteristics through standardized configuration patterns.
2Adaptability or versatility
If control transistors are connected to control wiring lines in all pixels, then charge accumulation capability is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent segments the control transistor connections into different types within the pixel array. Instead of uniformly connecting all control transistors to control wiring lines, the invention divides pixels into different categories based on their control transistor connection patterns. This segmentation reduces the overall complexity of control wiring while ensuring that each pixel type has the necessary charge accumulation capability for its specific function.
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 maintains uniform pixel output characteristics and improves the accuracy of distance measurement by preventing mixing of pixels with and without control transistors, enhancing the precision of distance calculations.
Implementation Method 1
each pixel including a photoelectric conversion element configured to generate electric charges corresponding to incident light
Data Source
AI summary
A distance image capturing element includes a pixel array in which a plurality of pixels, each having a photoelectric conversion element and N (N≥2) charge accumulation units, are arranged, and a pixel drive circuit configured to drive the pixels to distribute and accumulate electric charges in each charge accumulation unit. The pixel includes the N transfer transistors configured to transfer the electric charges from the photoelectric conversion element to each N charge accumulation unit, the N reset transistors configured to reset the charge accumulation units, and the N control transistors connected between the reset transistors and the power supply line. At least one control terminal among the N control transistors is connected to a control wiring line capable of controlling an ON state of the control transistors, and remaining control terminals other than the at least one control terminal are connected to fix the control transistors in an OFF state.