Image Sensor Micro-Lens Layout With Light-Blocking Cross-Talk Control

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Solution Overview

Problem

Image sensors experience optical cross-talk due to poor light control between adjacent micro-lens regions, leading to poor device performance.

Innovation Solution

Incorporating a planarization layer with a black photoresist between the substrate and color filters, which blocks light traveling between adjacent micro-lens, ensuring that light is directed to the appropriate pixel for processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If micro-lens array is used to direct light to pixels, then light directionality is improved, but optical cross-talk between adjacent pixels increases due to poor light control in regions between adjacent micro-lens

Engineering Contradiction:

Improvelight directionalityVSAvoidoptical cross-talk

Core Design Contradiction:

Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a light-blocking layer as an intermediary component positioned between the micro-lens array and the pixel array. This layer acts as a mediator that selectively blocks stray light and reflections from reaching adjacent pixels, thereby reducing optical cross-talk while preserving the light-directing function of the micro-lens array.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent addresses the two-dimensional light control problem by introducing a third dimension - a vertically positioned light-blocking layer. This layered structure adds depth to the optical path control, allowing selective blocking of light in the vertical dimension while maintaining horizontal light directionality through the micro-lens array.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Object-affected harmful factors

If light-blocking structures are added to reduce optical cross-talk, then optical cross-talk is reduced, but device complexity increases

Engineering Contradiction:

Improveoptical cross-talkVSAvoidstructure complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent employs a thin-film light-blocking layer that can be deposited as a continuous or patterned coating. This thin-film approach provides effective light blocking with minimal additional thickness, avoiding the need for bulky mechanical shutters or complex multi-layer structures, thereby reducing overall device complexity while maintaining optical performance.

Inventive Principle:

Principle #30Flexible shells and thin films

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 effectively minimizes optical cross-talk between adjacent pixels, enhancing the performance of image sensors by ensuring that light is properly directed and recorded.

Implementation Method 1

structure adapted for blocking light radiation that is traveling towards a region between adjacent micro-lens

Methodology Applied

Scientific EffectLight blocking: Absorption (EM radiation)

Data Source

PatentUS11756972B2Apparatus for reducing optical cross-talk in image sensors

Publication Date: 2023.09.12 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

According to one example, a device includes a semiconductor substrate. The device further includes a plurality of color filters disposed above the semiconductor substrate. The device further includes a plurality of micro-lenses disposed above the set of color filters. The device further includes a structure that is configured to block light radiation that is traveling towards a region between adjacent micro-lenses. The structure and the color filters are level at respective top surfaces and bottom surfaces thereof.