HMD Projector Assembly Alignment Using Altered Frame Mating Structure

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Solution Overview

Problem

Existing head-mounted displays suffer from optical deviations due to variations between light projectors, leading to suboptimal user experiences, as slight differences in projector alignment can be glaringly apparent to users.

Innovation Solution

A method and system for determining the optical angle of a display projector assembly relative to its base, altering a mating structure within a frame to align the output along a predetermined optical axis, and mating the assembly to the frame using an altered mating structure, ensuring precise optical alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If standard manufacturing tolerances are used for projector assemblies, then manufacturing cost and complexity are reduced, but optical alignment precision deteriorates leading to visible deviations

Engineering Contradiction:
Improveoptical alignment precisionVSAvoidalignment process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-determining the optical angle of each projector assembly before final assembly. The system measures and records the specific optical angle of each projector relative to its base, then uses this pre-determined information to calculate and alter the mating structure accordingly. This preliminary measurement and documentation of optical characteristics enables precise alignment to be achieved during assembly without requiring complex real-time adjustment mechanisms.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements parameter changes by physically altering the mating structure based on the determined optical angle. The system modifies geometric parameters of the mating structure (such as angle, position, or orientation) to compensate for variations in projector optical output. This parameter adjustment of the mating structure transforms the alignment process from requiring high-precision mechanical manufacturing to allowing standard tolerances while achieving precise optical alignment through controlled parameter modification.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If individual optical compensation is implemented for each projector variation, then optical quality is improved, but manufacturing time and cost increase

Engineering Contradiction:
Improveoptical alignment precisionVSAvoidassembly speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent replaces complex mechanical alignment adjustment mechanisms with a computational and structural modification approach. Instead of using adjustable mechanical components or manual alignment procedures during assembly, the system uses predetermined optical angle measurements combined with pre-calculated mating structure alterations. This substitution of mechanical adjustment systems with pre-computed structural solutions maintains high optical precision while enabling rapid assembly without time-consuming manual alignment procedures.

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

Solution Approach 2:

The system implements self-service by having each projector assembly determine its own optical angle characteristics, which then automatically informs the modification of its corresponding mating structure. The projector assembly essentially 'specifies' its own alignment requirements through the measurement process, and the mating structure is tailored to match these self-determined parameters. This self-service approach eliminates the need for external alignment expertise or complex adjustment procedures during assembly.

Inventive Principle:
Principle #25Self-service

3Stability of the object's composition

If thicker bonding structures are used to ensure alignment, then structural stability is improved, but device thickness and weight increase

Engineering Contradiction:
Improveoptical stabilityVSAvoiddevice thickness
Core Design Contradiction:
Stability of the object's compositionVSLength of moving object

Solution Approach 1:

The patent applies parameter changes by modifying the geometric parameters of the mating structure rather than increasing its physical dimensions. By adjusting angle, position, or orientation parameters of the mating structure based on predetermined optical measurements, the system achieves precise optical alignment and stable composition without requiring thicker bonding structures. This parameter-based approach maintains optical stability while keeping the device thin and lightweight.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4336246B1Apparatuses, systems, and methods for aligning display projector assemblies included in head-mounted displays
Publication Date: 2025.12.31 META PLATFORMS TECHNOLOGIES LLC
  • EP4336246B1 patent drawingFigure 1
  • EP4336246B1 patent drawingFigure 2
  • EP4336246B1 patent drawingFigure 3A~3E

AI summary

Disclosed methods of aligning display projector assemblies included in head-mounted displays may include (1) determining an optical angle of an output of a display projector assembly relative to a base of the display projector assembly, (2) physically altering, based on the determined optical angle of the output of the display projector assembly, a mating structure included within a frame such that, when the base of the display projector assembly is mated to the frame via the mating structure, the output of the display projector assembly is optically aligned with the frame along a predetermined optical axis, and (3) mating the base of the display projector assembly to the frame via the altered mating structure. Various other methods, systems, and apparatuses are also disclosed.