Near-Eye Display Aperture Array for Double Image Elimination

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Solution Overview

Problem

Head-mounted display devices face challenges in providing a wide field of view and user comfort due to the need for optical elements or waveguides that result in bulky designs, with issues like limited field of view and occlusion from the user's head, and existing solutions like Fresnel lenses or lenticular arrays fail to address these issues effectively, especially for near-eye applications.

Innovation Solution

A near-eye display system featuring a light source with pixels of 5 microns or less pitch and an aperture array with non-overlapping apertures centered on equilateral triangles, positioned between 2 mm and 5 mm from the light source, to selectively pass light without creating double images, combined with a lens array and standoff surface to enhance image focus and resolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If optical elements or waveguides are used in head-mounted displays, then the device can provide display functionality, but the device becomes thicker and more bulky

Engineering Contradiction:
Improvedisplay functionalityVSAvoiddevice thickness
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The patent removes traditional optical elements (lenses, waveguides) from the display system and replaces them with a direct retinal projection approach using a laser source and scanning mirrors. This extraction of bulky optical components achieves the desired thinness while maintaining display functionality through direct retinal stimulation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces mechanical optical systems (lenses, mirrors, waveguides) with a direct optical projection system that uses a laser source and electro-optical scanning. This substitution eliminates the need for complex mechanical optical paths while achieving the same display function through direct retinal projection.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If a steerable micro-mirror is positioned in front of the eye, then the beam can be scanned, but the user's field of view is limited

Engineering Contradiction:
Improvebeam scanning capabilityVSAvoidfield of view
Core Design Contradiction:
Ease of operationVSArea of stationary object

Solution Approach 1:

The patent uses a virtual image approach where the display content is projected to appear at a virtual distance from the eye. This creates a copy of the display content in virtual space, allowing the physical mirrors to be small while still providing a wide apparent field of view through the virtual image location.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent extends the field of view by utilizing the virtual distance dimension. By projecting images to a virtual location several meters away, the system effectively adds a spatial dimension that allows wide angular coverage without requiring large physical mirror surfaces in front of the eye.

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

3Volume of moving object

If a laser diode is mounted near the temple, then the device can be compact, but the mirroring surface must be strongly convex which is difficult to address for various pupil positions

Engineering Contradiction:
Improvedevice compactnessVSAvoidpupil position accommodation
Core Design Contradiction:
Volume of moving objectVSAdaptability or versatility

Solution Approach 1:

The patent employs dynamic eye tracking to monitor pupil position in real-time and dynamically adjusts the scanning parameters and beam direction accordingly. This dynamic adaptation allows a compact laser diode mounting position to accommodate various pupil positions and eye movements without requiring a strongly convex mirror surface.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses eye tracking feedback to detect pupil position and adjusts the scanning mirror control signals in response. This feedback mechanism enables the compact laser diode arrangement to adapt to different pupil positions, maintaining proper beam alignment without requiring complex mirror geometries.

Inventive Principle:
Principle #23Feedback

4Length of stationary object

If Fresnel lenses are used, then the device can be thinner, but they are designed for viewers far away and do not work effectively for near-eye applications

Engineering Contradiction:
Improvedevice thicknessVSAvoidnear-eye display performance
Core Design Contradiction:
Length of stationary objectVSReliability

Solution Approach 1:

The patent removes the Fresnel lens from the optical path entirely and replaces it with a direct retinal projection system. This extraction eliminates the fundamental mismatch between Fresnel lens design (for distant viewing) and near-eye application requirements, achieving both thinness and effective near-eye display performance.

Inventive Principle:
Principle #2Taking out (Extraction)

5Adaptability or versatility

If lenticular lenses or lens arrays are used, then angular dependence and stereo effect can be provided, but the image becomes blurry at close viewing ranges

Engineering Contradiction:
Improveangular dependence and stereo effectVSAvoidimage sharpness
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent replaces lenticular lens arrays with a direct retinal projection system using laser scanning. This substitution eliminates the optical limitations of lenticular systems at close range while maintaining angular dependence through dynamic scanning control. The laser beam can be precisely directed to different retinal locations, providing both angular coverage and sharp imagery at near-eye distances.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 system achieves a wide field of view and improved user comfort by avoiding double images and diffraction, enabling effective focus on near-eye displays without the bulkiness of traditional solutions, while maintaining high resolution and light intensity.

Implementation Method 1

The aperture array selectively passes the light emitted from the pixels to display the image without a double image condition

Methodology Applied
Scientific EffectLight transmission and optical selection: Refraction

Implementation Method 2

combined with a lens array and standoff surface to enhance image focus and resolution

Methodology Applied
Scientific EffectLight focusing: Lens

Data Source

PatentEP3014341B1Near eye display
Publication Date: 2020.03.11 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP3014341B1 patent drawingFigure 1
  • EP3014341B1 patent drawingFigure 2
  • EP3014341B1 patent drawingFigure 3

AI summary

A system and related methods for near-eye display of an image are provided. In one example, a near-eye display system includes a light source comprising a surface and a plurality of pixels having a pixel pitch of 5 microns or less. An aperture array is located between 2 mm and 5 mm from the surface of the light source. The aperture array comprises non-overlapping apertures that are each centered on a vertex of an equilateral triangle within a grid of equilateral triangles. The center of each aperture is spaced from the center of each adjacent aperture by an aperture spacing of between 1 mm and 9 mm. The aperture array selectively passes the light emitted from the pixels to display the image without a double image condition.