ToF Imaging Element Wiring Layout for Uniform Parasitic Capacitance

Solution Overview

Problem

In imaging elements using the ToF method, the generation of parasitic capacitances between adjacent wirings due to downsizing leads to non-uniform charge distribution, affecting distance measurement accuracy.

Innovation Solution

The arrangement of drive and fixed voltage wirings in the wiring layer ensures an equal number of adjacent wirings for each gate electrode, maintaining uniform parasitic capacitances and improving charge distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the imaging element is downsized to reduce module size, then miniaturization is achieved, but parasitic capacitance between adjacent wirings increases and becomes non-uniform

Engineering Contradiction:

Improvemodule sizeVSAvoidparasitic capacitance uniformity

Core Design Contradiction:

Volume of moving objectVSManufacturing precision

Solution Approach 1:

The patent applies local quality by configuring different wiring arrangements in different regions of the pixel array. Specifically, pixels in the central region have a different number of adjacent drive wirings compared to pixels in peripheral regions, compensating for the non-uniform parasitic capacitance that arises due to downsizing. This localized adjustment ensures uniform charge distribution across the entire array despite the reduced module size.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the parameter of wiring configuration by varying the number of adjacent drive wirings for different pixels based on their position in the array. This parameter modification compensates for the position-dependent parasitic capacitance variations that occur when the imaging element is downsized, thereby maintaining measurement precision across all pixels.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If the number of wirings is increased to support gate electrode driving, then charge distribution functionality is improved, but parasitic capacitance between adjacent wirings increases

Engineering Contradiction:

Improvecharge distribution functionalityVSAvoidparasitic capacitance

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by configuring different wiring arrangements in different regions of the pixel array. Specifically, pixels in the central region have a different number of adjacent drive wirings compared to pixels in peripheral regions, compensating for the non-uniform parasitic capacitance that arises due to downsizing. This localized adjustment ensures uniform charge distribution across the entire array despite the reduced module size.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the parameter of wiring configuration by varying the number of adjacent drive wirings for different pixels based on their position in the array. This parameter modification compensates for the position-dependent parasitic capacitance variations that occur when the imaging element is downsized, thereby maintaining measurement precision across all pixels.

Inventive Principle:

Principle #35Parameter changes

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 enhances distance measurement accuracy by ensuring uniform parasitic capacitances and consistent charge distribution, thereby improving the precision of distance measurements.

Implementation Method 1

reflected light obtained by light emitted from a light source hitting an object and being reflected is photoelectrically converted by a photodiode

Methodology Applied

Scientific EffectPhotoelectric conversion: Photoelectric Effect

Data Source

PatentUS20260050066A1Imaging element and distance measuring device

Publication Date: 2026.02.19 SONY SEMICON SOLUTIONS CORP

AI summary

An imaging element and a distance measuring device capable of making uniform parasitic capacitances generated between wirings for each wiring that include a photoelectric conversion unit; first and second charge storage units; a first transfer unit; a second transfer unit; and a wiring layer, in which a first wiring connected to the first transfer unit and a second wiring connected to the second transfer unit are arranged in the wiring layer, a drive wiring to supply a drive signal or/and a fixed voltage wiring to supply a predetermined voltage are arranged therein, and the number of the drive wirings or/and the fixed voltage wirings adjacent to the first wiring, and the number of the drive wirings or/and the fixed voltage wirings adjacent to the second wiring are the same. The present technology can be applied to, for example, an imaging element having a plurality of taps and performing distance measurement.