Stacked Polychrome Micro-Display Integration Without Combiner Optics

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Solution Overview

Problem

Current polychrome micro-display technologies for Augmented Reality applications are cost-intensive and voluminous due to the need for separate monochrome dies and complex optical combinations, making them incompatible with existing CMOS foundries and inefficient in terms of integration and volume.

Innovation Solution

A method for manufacturing polychrome displays or imaging devices by processing multiple semiconductor wafers with different light emission or detection capabilities, bonding them in a stacked manner, and integrating them with a CMOS backplane, allowing for individual addressing and optimization of each pixel's wavelength, thereby reducing volume and increasing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If separate monochrome dies with combiner optics are used for polychrome displays, then polychrome display functionality is achieved, but manufacturing cost increases and device volume increases

Engineering Contradiction:
Improvepolychrome display functionalityVSAvoidmanufacturing complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple monochrome light emitting device layers (e.g., red, green, blue) into a single integrated polychrome light emitting device structure. This merging eliminates the need for separate monochrome dies and combiner optics, thereby reducing manufacturing complexity and device volume while maintaining polychrome display functionality.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent transitions from a planar arrangement of separate monochrome dies to a three-dimensional stacked structure where multiple light emitting device layers are vertically integrated. This dimensional change enables compact integration of multiple colors within a single device footprint, reducing overall device volume and simplifying the optical combining system.

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

2Adaptability or versatility

If separate monochrome dies with combiner optics are used for polychrome displays, then polychrome display functionality is achieved, but device volume increases

Engineering Contradiction:
Improvepolychrome display functionalityVSAvoiddevice volume
Core Design Contradiction:
Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The patent merges multiple monochrome light emitting device layers into a single integrated structure, eliminating the need for separate dies and combiner optics. This consolidation dramatically reduces the overall device volume by integrating multiple functions into one compact unit.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements a nested structure where multiple light emitting device layers (red, green, blue) are stacked vertically within a single device envelope. Each layer is nested within the same structural boundary, enabling compact integration of multiple colors without increasing the device footprint or overall volume.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Manufacturing precision

If multiple separate semiconductor wafers are processed and bonded for polychrome devices, then manufacturing precision and wavelength optimization are improved, but process complexity increases

Engineering Contradiction:
Improvewavelength optimizationVSAvoidintegration process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent segments the manufacturing process by processing each color layer (red, green, blue) on separate semiconductor wafers independently, allowing for optimized epitaxial growth and wavelength tuning for each color. After individual processing, the wafers are bonded together in a stacked configuration, combining the benefits of specialized processing with integrated functionality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent resolves process complexity by transitioning to a vertical stacking architecture where multiple processed wafers are bonded in the third dimension. This vertical integration allows each wafer to be independently optimized for its specific wavelength while maintaining a compact integrated structure, separating the complexity of individual processing from the simplicity of final 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 approach enables the creation of compact, high-resolution polychrome displays or imaging devices that can operate on different wavelengths, driven by a single ASIC, with optimized optical coupling and isolation, facilitating a cost-effective and high-volume manufacturing process compatible with existing CMOS fabs.

Implementation Method 1

bonding the first semiconductor wafer, at least the second semiconductor wafer, and the third semiconductor wafer in a stacked manner

Methodology Applied
Scientific EffectWafer bonding: Welding

Implementation Method 2

processing a plurality of first semiconductor light emitting or detecting devices on a first semiconductor wafer, each configured to emit or detect light of a first color

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP4303926A1Method for manufacturing polychrome devices and polychrome display device
Publication Date: 2024.01.10 MICLEDI MICRODISPLAYS BV
  • EP4303926A1 patent drawingFigure 1
  • EP4303926A1 patent drawingFigure 2A~2B
  • EP4303926A1 patent drawingFigure 3A~3B

AI summary

A method (100) is provided for manufacturing a polychrome display or imaging device. The method comprises the steps of processing (101) a plurality of first semiconductor light emitting or detecting devices on a first semiconductor wafer, each configured to emit or detect light of a first color, processing (102) at least a plurality of second semiconductor light emitting or detecting devices on at least a second semiconductor wafer, each configured to emit or detect light of a second color, processing (103) an integrated circuit with driving devices for driving the plurality of first semiconductor light emitting or detecting devices and the plurality of second semiconductor light emitting or detecting devices on a third semiconductor wafer, and bonding (104) the first semiconductor wafer, at least the second semiconductor wafer, and the third semiconductor wafer in a stacked manner.