Stacked Image Sensor Color Separation for Light Efficiency

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Solution Overview

Problem

Color filters in image sensors and displays have low light use efficiency due to absorption of most incident light, leading to optical losses and varying pixel sensitivities caused by angle-dependent color separation efficiency.

Innovation Solution

A stacked image sensor design with color separation elements between two light sensing layers, directing specific wavelength bands to corresponding pixels, and using a transparent dielectric layer to cover these elements, ensuring consistent color separation efficiency across different angles and improving light transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If color filters are used to detect colors in image sensors, then color detection capability is achieved, but light use efficiency deteriorates due to absorption of most incident light

Engineering Contradiction:

Improvelight use efficiencyVSAvoidoptical loss

Core Design Contradiction:

Use of energy by moving objectVSLoss of energy

Solution Approach 1:

A color separation element is introduced as an intermediary component between the incident light and the pixel array. This element separates incident light into different wavelength bands and directs each band to corresponding pixels, replacing the traditional color filter approach and significantly improving light use efficiency while reducing optical loss.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the absorption-based color filtering mechanism with a refraction-based color separation mechanism. Instead of using color filters that absorb most incident light, the system uses color separation elements that refract and direct different wavelength bands to appropriate pixels, thereby substituting a less efficient mechanical/optical system with a more efficient one.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Use of energy by moving object

If color separation elements are used to improve light use efficiency, then light transmission is improved, but pixel sensitivity uniformity deteriorates due to angle-dependent color separation efficiency

Engineering Contradiction:

Improvelight use efficiencyVSAvoidpixel sensitivity uniformity

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The color separation element employs an asymmetric structure with different refractive indices for light entering from different directions. This asymmetric design compensates for the angle-dependent color separation efficiency by directing light from various angles to the correct pixels, thereby maintaining uniform pixel sensitivity across the sensor array while preserving high light use efficiency.

Inventive Principle:

Principle #4Asymmetry

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

Enhances light use efficiency and maintains consistent pixel sensitivity by effectively separating and directing different wavelengths, reducing optical losses and improving image resolution and quality.

Implementation Method 1

The color separation elements may separate colors of incident light based on diffraction or refraction characteristics of light varying according to wavelengths of light

Methodology Applied

Scientific EffectDiffraction: Diffraction

Implementation Method 2

The color separation elements may separate colors of incident light based on diffraction or refraction characteristics of light varying according to wavelengths of light

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 3

a first light sensing layer including first pixels configured to absorb and detect light of a first wavelength band and transmit light of a second wavelength band and a third wavelength band

Methodology Applied

Scientific EffectAbsorption: Absorption (EM radiation)

Implementation Method 4

using a transparent dielectric layer to cover these elements, ensuring consistent color separation efficiency across different angles and improving light transmission

Methodology Applied

Scientific EffectDielectric: Dielectric

Data Source

PatentUS9536916B2Stacked type image sensor including color separation element and image pickup apparatus including stacked type image sensor

Publication Date: 2017.01.03 SAMSUNG ELECTRONICS CO LTD

AI summary

A stacked type image sensor including color separation elements, and an image pickup apparatus including the stacked type image sensor, are provided. The stacked type image sensor includes a first light sensing layer including first pixels configured to absorb and detect light of a first wavelength band and transmit light of a second wavelength band and a third wavelength band, and a second light sensing layer disposed to face the first light sensing layer, the second light sensing layer including second pixels configured to detect light of the second wavelength band and third pixels configured to detect light of the third wavelength band. The color separation elements are disposed between the first light sensing layer and the second light sensing layer, and are configured to direct the light of the second wavelength band toward the second pixels, and direct the light of the third wavelength band toward the third pixels.