Color Filter with Selective Blue Layer for Solid-State Imaging

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Solution Overview

Problem

Solid-state imaging devices face issues with flare, frame-like unevenness, and noise in captured images due to difficulties in forming even color filters and effectively shielding light from surrounding circuits, leading to degraded image quality.

Innovation Solution

A color filter configuration with multiple colored layers (red, green, and blue) is implemented, where the blue layer covers the surrounding area and side surfaces, and a fourth layer with lower transmittance is used to cover the colored arrays in the surrounding area, reducing light reflectance and improving image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a coating film is formed by spin coat method from center to periphery, then the color filter can be manufactured, but the coating film becomes thinner at the periphery causing frame-like unevenness in captured images

Engineering Contradiction:

Improvecoating film formationVSAvoidfilm thickness uniformity

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent extracts the color filter formation process into two separate steps: first, a coating film is formed by spin coat method; second, the blue colored layer is formed only in the surrounding area by selective coating and patterning. This separation allows the coating film to be formed uniformly across the entire substrate including the periphery, eliminating frame-like unevenness while still providing light reflection prevention in the surrounding area.

Inventive Principle:

Principle #2Taking out (Extraction)

2Manufacturing precision

If the color filter is formed with even thickness, then manufacturing precision is improved, but it becomes difficult to sufficiently shield light from the surrounding circuit

Engineering Contradiction:

Improvecolor filter thickness uniformityVSAvoidlight shielding

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies different structures to different regions: in the pixel area, a standard color filter with multiple colored layers is formed to ensure even thickness and manufacturing precision; in the surrounding area, the blue colored layer is formed with extended coverage to provide enhanced light shielding for the surrounding circuit. This local differentiation allows both even thickness in the pixel area and sufficient light shielding in the surrounding area.

Inventive Principle:

Principle #3Local quality

3Object-affected harmful factors

If the blue colored layer covers the surrounding area and side surfaces, then light reflection is reduced and flare is suppressed, but device complexity increases

Engineering Contradiction:

Improveflare suppressionVSAvoidcolor filter structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent segments the color filter structure into two parts: the pixel area with multiple colored layers (red, green, blue) arranged in colored arrays, and the surrounding area with only the blue colored layer. This segmentation simplifies the overall structure by removing unnecessary colored layers from the surrounding area while maintaining effective flare suppression through the blue layer's selective coverage of the surrounding area and side surfaces.

Inventive Principle:

Principle #1Segmentation

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 flare and noise, enhances image quality by ensuring even thickness of the color filter layers and adequate shielding of light from the surrounding circuit, thereby improving the overall performance of solid-state imaging devices.

Implementation Method 1

a blue colored layer that has high light transmittance in a blue wavelength band and that allows light from a subject image to transmit therethrough

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

a first colored layer that has high light transmittance in a first wavelength band and that allows light from a subject image to transmit therethrough and a second colored layer that has high light transmittance in a second wavelength band different from the first wavelength band

Methodology Applied

Scientific EffectSelective light transmission: Filter (optical)

Data Source

PatentUS7786426B2Imaging device with a color filter that contains a layer only covering the surrounding areas

Publication Date: 2010.08.31 SONY SEMICON SOLUTIONS CORP

AI summary

There is provided a solid-state imaging device including a substrate of which surface is provided with a pixel area where a plurality of pixels arranged, each pixel including a photoelectric converting element to receive light from a subject image and perform photoelectric conversion on the received light to generate signal charge, and a surrounding area that is positioned around the pixel area and that includes a surrounding circuit to process the signal charge generated by the photoelectric converting elements. The solid-state imaging device includes a color filter facing the substrate so as to receive the light from the subject image in a surface corresponding to the surface of the substrate and to allow the light to transmit therethrough onto the surface of the substrate. The color filter includes a first colored layer and a second colored layer.