Solid State Image Sensor Peripheral Shielding Against Flare and Ghosts

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Solution Overview

Problem

Existing imaging devices with solid state image sensors suffer from insufficient suppression of flare and ghosts due to inadequate light-shielding films, particularly when the infrared cut filter and glass substrate are separated, and when light is reflected at the end surface of the glass substrate in wafer level chip size package structures.

Innovation Solution

An integrated assembly is developed with a light shield arranged to block light at the periphery, where 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.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the infrared cut filter and glass substrate are separated, then the structure is simpler and easier to manufacture, but the light-shielding film becomes insufficient and flare and ghosts increase

Engineering Contradiction:

Improveease of manufactureVSAvoidflare and ghosts

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The light-shielding film is extended from the two-dimensional surface of the infrared cut filter to the three-dimensional peripheral surface of the glass substrate. By forming the light-shielding film on the peripheral portion of the glass substrate that surrounds the outer periphery, the shielding coverage is expanded into additional spatial dimensions, effectively blocking stray light paths that would otherwise cause flare and ghosts.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The light-shielding film is formed on the glass substrate before final assembly, ensuring that stray light is blocked at the earliest possible stage. This preliminary positioning of the light-shielding structure prevents harmful light from entering the optical path, thereby preventing flare and ghosts before they can occur during imaging.

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 manufacturing process is simpler, but the positional accuracy is insufficient and flare and ghosts are not sufficiently suppressed

Engineering Contradiction:

Improveease of manufactureVSAvoidpositional accuracy

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The printing process is replaced with a formation process on the glass substrate that achieves superior positional accuracy. By forming the light-shielding film directly on the glass substrate peripheral portion rather than printing on the infrared cut filter, the system achieves precise positioning without relying on printing alignment, thereby eliminating flare and ghosts with high manufacturing precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Object-affected harmful factors

If the light-shielding film is arranged at the front stage of the solid state image sensor, then the stray light blocking is improved, but the positional accuracy remains insufficient

Engineering Contradiction:

Improvestray light blockingVSAvoidpositional accuracy

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The light-shielding function is merged with the glass substrate structure itself. By forming the light-shielding film on the peripheral portion of the glass substrate, the shielding function is integrated into the substrate rather than being a separate arranged component. This integration ensures both effective stray light blocking and high positional accuracy, as the light-shielding structure and substrate are formed together in the same manufacturing process.

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, enhancing the accuracy of light-shielding and improving image quality.

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)

Data Source

PatentUS20240006442A1Imaging device, solid state image sensor, and electronic device

Publication Date: 2024.01.04 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.