Image Sensor Glass Substrate Shielding for Flare Suppression

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Solution Overview

Problem

Existing integrated assemblies for solid state image sensors with a CSP structure face challenges in effectively suppressing flare and ghosts due to insufficient light-shielding films, particularly when the infrared cut filter and glass substrate are separated, leading to inadequate positional accuracy and measurement against stray light reflections.

Innovation Solution

An integrated assembly is designed with a light shield arranged to block light at the periphery, where a part of the light shield is disposed on transparent materials, and a light-shielding film is formed on the glass substrate's peripheral portion bonded to the imaging surface with high positional accuracy using a transparent adhesive, enhancing the suppression of flare and ghosts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the infrared cut filter and glass substrate are separated, then the assembly flexibility is improved, but the light-shielding effectiveness deteriorates

Engineering Contradiction:

Improveassembly flexibilityVSAvoidflare and ghosts

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

A light-shielding film is introduced as an intermediary element between the separated infrared cut filter and glass substrate. This film is formed on the peripheral portion of the glass substrate's light-receiving surface, acting as a mediator that maintains light-shielding effectiveness despite the separation of components for assembly flexibility.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The light-shielding function is transitioned from a three-dimensional spatial arrangement (relying on the position of the IRCF) to a two-dimensional surface feature (a film formed on the glass substrate periphery). This dimensional change allows the light-shielding effect to be maintained independently of the IRCF's positional relationship with the glass substrate.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Object-affected harmful factors

If the light-shielding film is formed on the IRCF peripheral portion, then the flare suppression is improved, but the positional accuracy deteriorates

Engineering Contradiction:

Improveflare suppressionVSAvoidpositional accuracy

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

Instead of forming the light-shielding film on the IRCF (the traditional approach), the invention inverts the approach by forming the film directly on the glass substrate's light-receiving surface. This inversion leverages the glass substrate's role as a reference element, achieving high positional accuracy while maintaining flare suppression effectiveness.

Inventive Principle:

Principle #13The other way round (Inversion)

3Ease of manufacture

If the light-shielding film is formed by printing, then the manufacturing ease is improved, but the positional accuracy deteriorates

Engineering Contradiction:

Improvemanufacturing easeVSAvoidpositional accuracy

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention replaces the mechanical printing process with a deposition process that forms the light-shielding film directly on the glass substrate. This substitution eliminates the limitations of printing-based positional accuracy while maintaining manufacturing feasibility, achieving both ease of manufacture and high positional accuracy.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 solution effectively prevents stray light penetration, significantly reducing the generation of flare and ghosts, thereby improving image quality by ensuring accurate light-shielding across the effective pixel region.

Implementation Method 1

a light shield arranged to block light at a periphery of the integrated assembly

Methodology Applied

Scientific EffectLight blocking: Absorption (EM radiation)

Implementation Method 2

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

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentUS11810935B2Imaging device, solid state image sensor, and electronic device

Publication Date: 2023.11.07 SONY SEMICON SOLUTIONS CORP

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.