Integrated Optical Filter Design for Thin Solid-State Imaging Devices

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Solution Overview

Problem

Existing solid-state imaging devices that incorporate Time of Flight (TOF) methods for both visible and near-infrared light detection are bulky due to separate optical filters and lack a thinning solution that maintains effective infrared blocking and visible light detection accuracy.

Innovation Solution

A solid-state imaging device design featuring a color filter layer for visible light detection and an infrared pass filter layer, with an infrared cut filter layer that blocks infrared light and is thinned using a cured film to integrate optical filters directly on the pixel array, reducing device thickness while maintaining high sensitivity and accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If separate optical filters are used for visible light detection and infrared blocking, then detection accuracy is maintained, but device thickness increases

Engineering Contradiction:

Improvedetection accuracyVSAvoiddevice thickness

Core Design Contradiction:

Measurement precisionVSLength of stationary object

Solution Approach 1:

The patent combines the infrared cut filter layer and color filter layer into a single integrated optical filter structure. The infrared cut filter layer (containing infrared-absorbing agents like diimmonium dyes or metal oxides) is integrated with the color filter layer on the pixel array, allowing both infrared blocking and visible light color separation to occur within the same filter assembly, thereby reducing overall device thickness while maintaining detection accuracy for both visible and infrared wavelengths.

Inventive Principle:

Principle #5Merging (Combining)

2Length of stationary object

If the infrared cut filter layer is thinned to reduce device thickness, then device compactness is improved, but infrared blocking performance deteriorates

Engineering Contradiction:

Improvedevice thicknessVSAvoidinfrared blocking performance

Core Design Contradiction:

Length of stationary objectVSReliability

Solution Approach 1:

The patent employs composite material strategies by combining multiple infrared-absorbing agents (such as diimmonium dyes and metal oxides like tungsten oxide or molybdenum oxide) within the infrared cut filter layer. This composite approach enhances the infrared blocking capability per unit thickness, allowing the filter layer to be thinned while maintaining effective infrared rejection. The synergistic effect of multiple absorbing agents compensates for the reduced thickness.

Inventive Principle:

Principle #40Composite materials

3Adaptability or versatility

If multiple light-receiving elements are provided for visible and infrared detection, then sensing functionality is enhanced, but device complexity increases

Engineering Contradiction:

Improvesensing functionalityVSAvoiddevice complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements a multi-functional pixel array where a single pixel array structure serves both visible light detection (with color filters for RGB detection) and infrared detection (with infrared pass filters). The integrated optical filter design allows the same pixel array to perform multiple sensing functions by selectively transmitting different wavelength ranges, thereby enhancing sensing functionality while avoiding the complexity of separate pixel arrays for visible and infrared detection.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

The integrated filter design enables thinner, more efficient solid-state imaging devices capable of accurate visible light detection and near-infrared ranging with reduced noise and improved light utilization efficiency.

Implementation Method 1

an infrared cut filter layer that is provided on a position overlapping with the color filter layer and transmits light in the visible light wavelength region by blocking light in an infrared wavelength region

Methodology Applied

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

Implementation Method 2

a cured film provided in contact with the infrared cut filter layer

Methodology Applied

Scientific EffectPressure distribution:

Data Source

PatentUS10854661B2Solid-state imaging device, infrared-absorbing composition, and flattened-film-forming curable composition

Publication Date: 2020.12.01 JSR CORPORATION

AI summary

Provided is a solid-state imaging device that includes: a first pixel provided with a color filter layer having a transmission band in a visible light wavelength region on a light-receiving surface of a first light-receiving element; a second pixel provided with an infrared pass filter layer having a transmission band in an infrared wavelength region on a light-receiving surface of a second light-receiving element; an infrared cut filter layer that is provided on a position overlapping with the color filter layer and transmits light in the visible light wavelength region by blocking light in the infrared wavelength region; and a cured film provided in contact with the infrared cut filter layer.