Hemispherical Color Filter and Isolation Layer for Image Sensor Crosstalk

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Solution Overview

Problem

Existing image sensors experience light loss and crosstalk at the edge portions due to oblique light incidence, leading to inaccurate color detection and reduced light use efficiency.

Innovation Solution

An image sensor design featuring a light-sensing layer with a color filter layer and an isolation layer, where the color filters have cylindrical upper portions and hemispherical lower portions, and an isolation layer with a refractive index less than the color filters, preventing light from being incident on adjacent pixels and enhancing optical isolation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If color filters are placed at edge portions of the image sensor, then the sensor can detect light at edge portions, but light loss and crosstalk occur due to oblique light incidence

Engineering Contradiction:

Improveactive area of image sensorVSAvoidlight loss

Core Design Contradiction:

Area of stationary objectVSLoss of energy

Solution Approach 1:

The color filter at the edge portion is formed with a hemispherical lower surface instead of a flat surface. This curved geometry allows obliquely incident light to be refracted and directed toward the light-sensing cell, improving light capture efficiency at edge portions while preventing light loss

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

An isolation layer with refractive index matching the color filter material is introduced between adjacent color filters. This intermediary layer prevents optical crosstalk by matching refractive indices, eliminating interface reflections and light scattering that would otherwise cause crosstalk between neighboring pixels

Inventive Principle:

Principle #24Intermediary (Mediator)

2Area of stationary object

If color filters are placed at edge portions of the image sensor, then the sensor can detect light at edge portions, but crosstalk occurs between adjacent pixels

Engineering Contradiction:

Improveactive area of image sensorVSAvoidcrosstalk

Core Design Contradiction:

Area of stationary objectVSObject-generated harmful factors

Solution Approach 1:

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The hemispherical lower surface of the color filter directs light rays toward the center of the corresponding light-sensing cell, preventing oblique light from reaching adjacent pixels and thus reducing crosstalk

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Ease of manufacture

If conventional flat color filters are used, then manufacturing is simple, but light use efficiency is reduced at edge portions

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidlight use efficiency

Core Design Contradiction:

Ease of manufactureVSUse of energy by moving object

Solution Approach 1:

The color filter is formed with a hemispherical lower surface, which can be manufactured using standard photolithography and etching processes. This curved geometry allows obliquely incident light to be refracted and directed toward the light-sensing cell, improving light capture efficiency at edge portions while preventing light loss

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The color filter structure is differentiated between central and edge portions: central pixels use flat color filters while edge pixels use hemispherical color filters. This local adaptation optimizes light capture for each position's specific incident angle requirements without complicating the overall manufacturing process

Inventive Principle:

Principle #3Local quality

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 design effectively prevents light loss and crosstalk, improving light use efficiency and enabling accurate color detection even at edge portions of the image sensor.

Implementation Method 1

a color filter layer disposed on the light-sensing layer, the color filter layer including color filters, each of the color filters being configured to transmit, among the incident light, light in a wavelength band to the light-sensing layer

Methodology Applied

Scientific EffectOptical filtering: Filter (optical)

Implementation Method 2

an isolation layer disposed between the color filters, the isolation layer being configured to optically isolate the color filters from each other. The isolation layer may have a refractive index less than refractive indices of the color filters

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 3

a lower portion of each of the color filters has a hemispherical shape

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS9653501B2Image sensor including color filter and method of manufacturing the image sensor

Publication Date: 2017.05.16 SAMSUNG ELECTRONICS CO LTD

AI summary

An image sensor including a color filter and a method of manufacturing the image sensor are provided. The image sensor includes a light-sensing layer configured to detect incident light, and convert the incident light to an electrical signal. The image sensor further includes a color filter layer disposed on the light-sensing layer, the color filter layer including color filters, each of the color filters being configured to transmit, among the incident light, light in a wavelength band to the light-sensing layer. The image sensor further includes an isolation layer disposed between the color filters, the isolation layer being configured to optically isolate the color filters from each other. An upper portion of each of the color filters has a cylindrical shape, and a lower portion of each of the color filters has a hemispherical shape.