CAPD Sensor Pixel Substrate Light Converging Structure

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Solution Overview

Problem

Conventional Current Assisted Photonic Demodulator (CAPD) sensors lack a converging structure, leading to increased distance measurement errors due to signal charges being conducted to inactive taps, which reduces transfer efficiency and increases measurement errors.

Innovation Solution

Incorporating a converging portion on the substrate of the imaging element to focus light between signal extraction portions, enhancing the transfer of signal charges to active taps and reducing errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If photoelectric conversion is performed on the entire surface of the pixel substrate without a converging structure, then the pixel can capture light from a wide area, but signal charges are conducted to inactive taps, reducing transfer efficiency and increasing distance measurement errors

Engineering Contradiction:
Improvedistance measurement accuracyVSAvoidsignal charge transfer efficiency
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The pixel substrate is divided into distinct regions: a light receiving region where photoelectric conversion occurs and signal charges are generated, and a non-light receiving region where inactive taps are located. This segmentation prevents signal charges from being conducted to inactive taps, thereby improving transfer efficiency and reducing distance measurement errors while maintaining wide-area light capture capability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the pixel substrate are assigned different functions: the light receiving region is optimized for photoelectric conversion with appropriate structural features, while the non-light receiving region is configured to prevent signal charge conduction. This local differentiation ensures that signal charges generated in the light receiving region are directed only to active taps, improving both transfer efficiency and measurement accuracy

Inventive Principle:
Principle #3Local quality

2Measurement precision

If a converging structure is added to focus light between signal extraction portions, then transfer efficiency increases and distance measurement errors decrease, but device complexity increases

Engineering Contradiction:
Improvedistance measurement accuracyVSAvoidpixel structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The pixel substrate is segmented into a light receiving region and a non-light receiving region, eliminating the need for complex converging structures. This segmentation approach achieves improved transfer efficiency and measurement accuracy while maintaining relatively simple device architecture

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The problematic converging structure is extracted/removed from the design. Instead of adding complexity with converging elements, the patent uses regional segmentation to achieve the desired signal charge distribution, thereby improving measurement precision without significantly increasing device complexity

Inventive Principle:
Principle #2Taking out (Extraction)

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

The implementation of a converging portion on the substrate increases transfer efficiency and reduces distance measurement errors by ensuring signal charges are directed to the correct taps, thereby improving pixel sensitivity and accuracy.

Implementation Method 1

a substrate that performs photoelectric conversion of light having entered

Methodology Applied
Scientific EffectPhotoelectric conversion: Photoelectric Effect

Implementation Method 2

a first signal extraction portion including an application electrode to generate an electric field by application of a voltage

Methodology Applied
Scientific EffectElectric field generation: Electric Field

Data Source

PatentEP3550273B1Image capturing element and image capturing device
Publication Date: 2021.07.28 SONY SEMICON SOLUTIONS CORP
  • EP3550273B1 patent drawingFigure 1
  • EP3550273B1 patent drawingFigure 2
  • EP3550273B1 patent drawingFigure 3~4

AI summary

The present technology relates to an imaging element and an imaging device that enables reduction of a distance measurement error. The solid-state imaging device includes a pixel array unit including a plurality of pixels that performs photoelectric conversion of light having entered, in which each of the pixels includes: a substrate that performs photoelectric conversion of the light having entered; a first signal extraction portion including an application electrode to generate an electric field by application of a voltage and an attraction electrode to detect a signal carrier generated by photoelectric conversion; a second signal extraction portion including the application electrode and the attraction electrode; and a converging portion that is formed on the substrate and causes the light to enter the substrate. The converging portion converges the light at least between the first signal extraction portion and the second signal extraction portion provided in the substrate. The present technology can be applied to a CAPD sensor.