Distance Imaging Pixel Layout for Uniform Time-of-Flight 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 control, then the functionality of charge distribution and accumulation is improved, but the symmetry of pixel structure deteriorates and pixel output characteristic uniformity decreases
Solution Approach 1:
The patent applies local quality by making control transistors selectively present or absent in different pixels based on their specific functional requirements. Some pixels include control transistors for charge accumulation control while others omit them, allowing each pixel to have customized characteristics suited to its role in the imaging array.
Solution Approach 2:
The patent segments the pixel array into different types of pixels - some with control transistors and some without - rather than requiring all pixels to have identical structures. This segmentation allows the system to achieve both enhanced functionality where needed and maintained uniformity where appropriate.
2Ease of operation
If control transistors are added to all pixels, then charge accumulation control is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent implements control transistors only in pixels where charge accumulation control is required, rather than uniformly across all pixels. This localized approach provides the necessary operational control while avoiding the added complexity and manufacturing burden that would result from including control transistors in every pixel.
3Adaptability or versatility
If pixels with and without control transistors are mixed, then functional flexibility is improved, but measurement accuracy deteriorates due to non-uniform pixel output characteristics
Solution Approach 1:
The patent strategically places control transistors in specific pixels based on their functional requirements while maintaining uniformity in other pixels. This localized differentiation allows functional flexibility where needed while preserving measurement accuracy in regions where uniform pixel characteristics are critical for distance measurement.
Solution Approach 2:
The patent segments the imaging array into distinct functional zones - some pixels with control transistors for enhanced functionality and others without for maintained uniformity and accuracy. This segmentation allows the system to simultaneously achieve functional flexibility and measurement precision by assigning different roles to different pixel groups.
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 uniformity of pixel output characteristics, enhancing the accuracy of distance measurement by preventing mixing of pixels with and without control transistors.
Implementation Method 1
each pixel including a photoelectric conversion element configured to generate electric charges corresponding to incident light
Data Source
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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 plurality of pixels to distribute and accumulate electric charges in each of the charge accumulation units, in which the pixel includes the N transfer transistors configured to transfer the electric charges from the photoelectric conversion element to each of the N charge accumulation units, 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, and in the pixel, 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.