Stacked RGBZ Sensor Merging Visible and IR Arrays

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Solution Overview

Problem

Integrating time-of-flight depth capturing capabilities into mobile computing systems with traditional image capture functions poses design challenges such as increased cost and packaging complexities, as existing solutions often require separate packages for RGB and Z pixels.

Innovation Solution

A stacked semiconductor chip RGBZ sensor is developed, where a first pixel array sensitive to visible light is stacked on top of a second pixel array sensitive to IR light, allowing for simultaneous visible image capture and time-of-flight depth detection within a single camera package, reducing size and cost by integrating both functionalities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate packages are used for RGB and Z pixels, then each sensor can be optimized independently, but device size and packaging complexity increase

Engineering Contradiction:
Improvesensor optimizationVSAvoidpackaging complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines RGB and Z pixel arrays into a single stacked sensor package, where the RGB pixel array is positioned on one substrate and the Z pixel array on another substrate, with both arrays optically coupled to a common lens assembly. This merging eliminates the need for separate packages while maintaining independent optimization capabilities for each sensor type.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent transitions from a planar arrangement to a three-dimensional stacked configuration by positioning pixel arrays on separate substrates that are optically coupled through a lens assembly. This dimensional change allows both RGB and Z sensors to coexist in a compact volume without requiring lateral separation, thus reducing packaging complexity while maintaining performance.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If separate packages are used for RGB and Z pixels, then each sensor can be optimized independently, but overall device size increases

Engineering Contradiction:
Improvesensor optimizationVSAvoiddevice size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent merges RGB and Z pixel arrays into a single integrated sensor unit with shared optical components, significantly reducing the overall device volume compared to separate packages.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements a nested configuration where one pixel array is positioned on a substrate that is optically coupled to another pixel array through a lens assembly, creating a compact stacked structure that minimizes device footprint.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Device complexity

If a single package integrates both RGB and Z pixels, then device size and cost are reduced, but design complexity increases

Engineering Contradiction:
ImprovepackagingVSAvoiddesign complexity
Core Design Contradiction:
Device complexityVSEase of manufacture

Solution Approach 1:

The patent segments the integrated sensor into distinct modules: an RGB pixel array on one substrate, a Z pixel array on another substrate, and a lens assembly that optically couples both arrays. This segmentation allows each module to be independently optimized and manufactured before final integration, reducing design complexity while maintaining the benefits of a single package.

Inventive Principle:
Principle #1Segmentation

4Adaptability or versatility

If traditional image capture and depth capturing are integrated, then imaging capability is enhanced, but cost increases

Engineering Contradiction:
Improveimaging capabilityVSAvoidcost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent merges traditional image capture (RGB) and depth capturing (Z) functionalities into a single sensor package with shared optical components, eliminating the need for separate cameras and reducing overall system cost while enhancing imaging versatility.

Inventive Principle:
Principle #5Merging (Combining)

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 stacked RGBZ sensor effectively reduces size and cost while enabling simultaneous 2D image capture and 3D depth profiling, enhancing imaging capabilities without interfering with traditional imaging functions.

Implementation Method 1

a photoelectric conversion element layer containing a photoelectric conversion element that photoelectrically converts incident light

Methodology Applied
Scientific EffectPhotoelectric conversion: Photoelectric Effect

Implementation Method 2

an infrared sensor configured to detect the wavelengths of infrared light passed through the first color filter

Methodology Applied
Scientific EffectInfrared detection: Infrared Radiation

Data Source

PatentEP3238274B1Stacked semiconductor chip RGBZ sensor
Publication Date: 2022.12.21 GOOGLE LLC
  • EP3238274B1 patent drawingFigure 1a
  • EP3238274B1 patent drawingFigure 1b
  • EP3238274B1 patent drawingFigure 2

AI summary

An apparatus is described that includes a first semiconductor chip having a first pixel array. The first pixel array has visible light sensitive pixels. The apparatus includes a second semiconductor chip having a second pixel array. The first semiconductor chip is stacked on the second semiconductor chip such that the second pixel array resides beneath the first pixel array. The second pixel array has IR light sensitive pixels for time-of-flight based depth detection.