MEMS Scanning Display Using Interlaced Multi-Laser Segmentation

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Solution Overview

Problem

Current MEMS scanning display technology is limited by upper bounds on mirror scan rates, which restricts display resolution, particularly for near-eye applications where higher resolutions like 1440p or 2160p are desired, and increasing scan rates leads to increased power consumption and diffraction issues.

Innovation Solution

The use of multiple lasers in an interlaced mode with variable scan rates and phase offsets between interlaced frames, combined with eye-tracking sensors to dynamically adjust laser output based on user gaze direction, allows for higher resolution without increasing mirror scan frequencies and permits larger mirrors to mitigate diffraction limitations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If mirror scan rate is increased to achieve higher display resolution, then display resolution is improved, but power consumption increases and diffraction issues occur

Engineering Contradiction:
Improvedisplay resolutionVSAvoidpower consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The patent divides the scanning task into multiple segments by using multiple laser sources (e.g., multiple red, green, and blue lasers) that scan different portions of the image. Each laser operates at a lower scan rate while collectively achieving high resolution through interlaced scanning patterns. This segmentation allows the system to achieve 1440p or 2160p resolution without requiring each individual mirror to scan at prohibitively high speeds, thereby reducing power consumption and avoiding diffraction issues.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If mirror scan rate is increased to achieve higher display resolution, then display resolution is improved, but diffraction issues occur

Engineering Contradiction:
Improvedisplay resolutionVSAvoiddiffraction issues
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

By segmenting the scanning task across multiple laser sources operating at lower frequencies, the patent avoids the diffraction issues that arise from high-speed single-laser scanning. Each laser operates at a manageable scan rate that prevents diffraction, while the combined output of multiple lasers achieves the desired high resolution through interlaced scanning patterns.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a single-laser scanning approach to a multi-laser approach, adding the dimension of multiple light sources. This dimensional change allows the system to achieve high resolution through spatial distribution of multiple lower-frequency scan patterns rather than relying on a single high-frequency scan, thereby eliminating diffraction problems.

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

3Device complexity

If single laser scans entire image, then device complexity is low, but scan rate must be very high to achieve high resolution

Engineering Contradiction:
Improvenumber of lasersVSAvoidmirror scan rate
Core Design Contradiction:
Device complexityVSSpeed

Solution Approach 1:

The patent segments the image scanning task across multiple laser sources, with each laser responsible for scanning a specific portion of the image. This segmentation allows each laser to operate at a lower, more manageable scan rate while collectively achieving high resolution through interlaced scanning patterns, eliminating the need for prohibitively high single-laser scan rates.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs periodic interlaced scanning patterns where multiple lasers alternate in scanning different portions of the image. This periodic action distributes the scanning load over time and space, allowing each laser to complete its portion at a lower frequency while maintaining overall high resolution through the coordinated periodic operation of all lasers.

Inventive Principle:
Principle #19Periodic action

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 higher display resolutions without the power consumption and diffraction issues associated with faster scan rates, providing sharper images and consistent brightness across the field-of-view.

Implementation Method 1

laser light is reflected by a scanning mirror system

Methodology Applied
Scientific EffectLaser: Laser

Implementation Method 2

laser light is reflected by a scanning mirror system at different angles to scan the laser across pixels

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP3589999B1MEMS scanning display device
Publication Date: 2024.04.17 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP3589999B1 patent drawingFigure 1
  • EP3589999B1 patent drawingFigure 2
  • EP3589999B1 patent drawingFigure 3

AI summary

Examples are disclosed that related to scanning image display systems. In one example, a scanning display system comprises a laser light source comprising two or more offset lasers, a scanning mirror system configured to scan light from the laser light source in a first direction at a higher frequency, and in a second direction at a lower frequency to form an image, and a controller configured to control the scanning mirror system to scan the laser light an interlaced pattern to form the image, and to adjust one or more of a scan rate in the second direction and a phase offset between a first frame and a second frame of the interlaced image.