Image Sensor Glass Substrate Shielding for Flare and Ghost Suppression

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Solution Overview

Problem

Existing technologies for solid state image sensors with a CSP structure fail to adequately suppress flare and ghosts due to insufficient light-shielding films, particularly when the infrared cut filter and glass substrate are separated, and the light-shielding films are not accurately positioned.

Innovation Solution

A light-shielding film is formed on the peripheral portion of a glass substrate bonded to the imaging surface of a solid state image sensor using a transparent adhesive, ensuring high positional accuracy and effective coverage up to the boundary of the pixel array to prevent stray light penetration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the infrared cut filter and glass substrate are separated, then the glass substrate can be bonded to the imaging surface, but the light-shielding film becomes insufficient against flare and ghosts

Engineering Contradiction:
Improvebonding glass substrate to imaging surfaceVSAvoidflare and ghosts
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The light-shielding film is extended from the two-dimensional peripheral portion of the infrared cut filter to the three-dimensional end surface of the glass substrate, creating coverage in an additional spatial dimension that effectively blocks stray light paths causing flare and ghosts

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The light-shielding film is formed on the end surface of the glass substrate before bonding the glass substrate to the imaging surface, ensuring that the light-shielding structure is already in place to prevent flare and ghosts from the outset

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If the light-shielding film is formed by printing on the peripheral portion of the infrared cut filter, then the film can be applied, but the positional accuracy is insufficient

Engineering Contradiction:
Improveforming light-shielding film by printingVSAvoidpositional accuracy of light-shielding film
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The light-shielding film is formed to extend uniformly along the end surface of the glass substrate, creating an equipotential light-shielding barrier that maintains consistent coverage and positional accuracy regardless of the printing process variations

Inventive Principle:
Principle #12Equipotentiality

3Object-affected harmful factors

If the light-shielding film is arranged at the front stage of the solid state image sensor, then the film can provide protection, but the positional accuracy remains insufficient

Engineering Contradiction:
Improveprotection against flare and ghostsVSAvoidpositional accuracy
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The light-shielding film is merged with the end surface of the glass substrate, combining the light-shielding function with the structural component of the glass substrate itself, thereby eliminating separate positioning requirements and achieving high positional accuracy

Inventive Principle:
Principle #5Merging (Combining)

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 suppresses the generation of flare and ghosts by preventing stray light penetration, improving image quality and accuracy.

Implementation Method 1

bonding a glass substrate onto an imaging surface, using a transparent adhesive

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

a light-shielding film for suppressing generation of flare or ghosts is formed on a peripheral portion

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentEP3631858B1Imaging device, solid state image sensor, and electronic device
Publication Date: 2024.08.28 SONY SEMICON SOLUTIONS CORP
  • EP3631858B1 patent drawingFigure 1
  • EP3631858B1 patent drawingFigure 2
  • EP3631858B1 patent drawingFigure 3

AI summary

To suppress generation of flare and ghosts. A solid state image sensor includes: a pixel array configured to generate a pixel signal according to an amount of incident light by photoelectric conversion in units of pixels arranged in an array manner; a glass substrate bonded with a light-receiving surface of the pixel array; and a light-shielding film formed on a peripheral portion that is an outside of an effective pixel region of the pixel array, in which the light-shielding film is formed at a front stage of the glass substrate. The present disclosure can be adapted to an imaging device.