Spectral Filter Arrays for Image Sensor Wavelength Classification

Solution Overview

Problem

Existing image sensors with spectral filters can only classify wavelength bands into three sections (RGB), which limits color expression accuracy and object recognition performance, and current spectral filters are bulky and complex, making them unsuitable for integration on semiconductor chips.

Innovation Solution

A spectral filter design that includes multiple first and second filter arrays with band filters and unit filters, featuring reflecting plates, cavities with different central wavelengths, and an intermediate light absorption layer, allowing for more precise wavelength separation and compensation for central wavelength shifts due to changes in the chief ray angle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If spectral filters are used to improve color expression accuracy and object recognition performance, then wavelength classification precision is improved, but device complexity and size increase

Engineering Contradiction:

Improvewavelength classification precisionVSAvoidoptical element complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The spectral filter is divided into multiple filter arrays, each containing multiple filters with specific wavelength transmission characteristics. Each filter array corresponds to different wavelength bands, enabling fine-grained spectral classification without requiring a single complex filter structure

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent transitions from traditional bulky optical spectral filters to a planar filter array structure that can be integrated on semiconductor chips. By arranging multiple filters in two-dimensional arrays with different spatial positions and wavelength characteristics, the system achieves spectral classification in a compact form factor suitable for chip integration

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Measurement precision

If traditional spectral filters are used for special-purpose cameras, then wavelength separation capability is improved, but device size and bulkiness increase

Engineering Contradiction:

Improvewavelength separation capabilityVSAvoidfilter size

Core Design Contradiction:

Measurement precisionVSVolume of moving object

Solution Approach 1:

The spectral filter is divided into multiple filter arrays, each containing multiple filters with specific wavelength transmission characteristics. Each filter array corresponds to different wavelength bands, enabling fine-grained spectral classification without requiring a single complex filter structure

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent transitions from traditional bulky optical spectral filters to a planar filter array structure that can be integrated on semiconductor chips. By arranging multiple filters in two-dimensional arrays with different spatial positions and wavelength characteristics, the system achieves spectral classification in a compact form factor suitable for chip integration

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 enhances color expression accuracy and object recognition performance by enabling more nuanced wavelength separation and integration on semiconductor chips, reducing the complexity and size of the spectral filter.

Implementation Method 1

a plurality of cavities provided between the first reflecting plate and second reflecting plate, each of the plurality of cavities having central wavelengths of different wavelength bands among a plurality of wavelength bands

Methodology Applied

Scientific EffectResonance: Resonance

Implementation Method 2

an intermediate light absorption layer provided between the lower cavity layer and the upper cavity layer

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 3

a first reflecting plate; a second reflecting plate spaced apart from the first reflecting plate

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS20230349758A1Spectral filter, image sensor including the spectral filter, and electronic device including the spectral filter

Publication Date: 2023.11.02 SAMSUNG ELECTRONICS CO LTD

AI summary

Provided are a spectral filter, and an image sensor and an electronic device each including the spectral filter. The spectral filter includes a plurality of first filter arrays respectively including a plurality of band filters and a plurality of second filter arrays provided on the plurality of first filter arrays. The plurality of unit filters includes a first reflecting plate, a second reflecting plate provided above the first reflecting plate, and a plurality of cavities provided between the first and second reflecting plates and each having central wavelengths of different bands. Each of the plurality of cavities includes a lower cavity layer, a upper cavity layer, and an intermediate light absorption layer provided between the lower cavity layer and the upper cavity layer. Each of the plurality of band filters is configured to transmit light in a specific band, and two or more of the plurality of cavities are configured to have a same effective refractive index.