Laser Alignment Sensor for Binocular HMD Frame Deformation

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Solution Overview

Problem

Binocular head-mounted displays (HMDs) face challenges due to deformation, which leads to misalignment between the left and right image displays, resulting in a blurred or compromised image and poor user experience, caused by factors like misuse, poor fit, asymmetrical facial features, and environmental factors.

Innovation Solution

The implementation of a laser alignment sensor system with photo-detectors and a control system that monitors and corrects misalignment by using mechanical actuators to adjust the frame, ensuring proper alignment and image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a binocular HMD is worn on the user's head, then the user can see displayed information, but frame deformation causes misalignment between left and right image displays resulting in a blurred or compromised image

Engineering Contradiction:
Improveimage alignmentVSAvoidframe deformation
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies preliminary action by pre-positioning laser alignment sensors and photo-detectors to detect misalignment before it significantly degrades image quality. The system proactively monitors frame deformation and triggers realignment actions before the misalignment becomes severe enough to cause blurred or compromised images, preventing rather than merely correcting the problem.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback through a closed-loop system where photo-detectors continuously monitor the position of laser alignment sensors, detect misalignment caused by frame deformation, and provide real-time feedback to actuators. This feedback mechanism enables the system to dynamically adjust and maintain proper alignment between left and right image displays despite ongoing frame deformation from wearing the HMD.

Inventive Principle:
Principle #23Feedback

2Ease of operation

If the HMD frame is made flexible to accommodate different users, then ease of operation improves, but frame deformation increases causing misalignment

Engineering Contradiction:
Improvefit adjustmentVSAvoidalignment precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent applies self-service by enabling the HMD to automatically detect and correct its own misalignment issues. The laser alignment sensors and photo-detectors allow the device to self-monitor frame deformation, and the actuators automatically adjust components to self-correct alignment problems without requiring external intervention or manual recalibration by the user.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent implements parameter changes by dynamically adjusting the position of optical components or frame elements through actuators in response to detected misalignment. The system changes physical parameters such as component position or orientation to compensate for frame deformation, maintaining alignment precision despite the flexible frame adapting to different users' head shapes and sizes.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If laser alignment sensors are added to correct misalignment, then image quality improves, but device complexity increases

Engineering Contradiction:
Improvealignment precisionVSAvoidsensor system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies mechanics substitution by replacing complex mechanical alignment adjustment mechanisms with an optical sensing system. Instead of using intricate mechanical systems to physically align components during manufacturing and assembly, the patent uses laser alignment sensors and photo-detectors to optically detect misalignment, allowing for simpler mechanical structures while achieving high alignment precision through electronic sensing and actuation.

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 solution effectively reduces rotational deformations and misalignment, providing a clear and stable image by actively compensating for frame deformations, preventing user disorientation and improving the overall user experience.

Implementation Method 1

laser alignment sensor system with photo-detectors

Methodology Applied
Scientific EffectLaser: Laser

Implementation Method 2

photo-detectors that receive the light beams and generate signals indicative of the location where the light beams strike their surfaces

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentEP2742380B1Laser alignment of binocular head mounted display
Publication Date: 2017.07.12 GOOGLE LLC
  • EP2742380B1 patent drawingFigure 1
  • EP2742380B1 patent drawingFigure 2
  • EP2742380B1 patent drawingFigure 3

AI summary

A binocular head mounted display includes a frame, right and left displays, an alignment sensor, and a control system. The right and left displays display right and left images to a user and are mounted to the frame. The alignment sensor includes a first laser source mounted proximate to one of the right or left displays and a first photo-detector array mounted opposite the first laser source and proximate to an opposite one of the right or left displays. The first alignment sensor is mounted to measure misalignment between the right and left displays due to deformation of the frame about one or more rotational axes and to generate a signal that is indicative of the misalignment. The control system is coupled to the alignment sensor to receive the signal and to calculate the misalignment based at least in part upon the signal.