Adjustable HMD Collimating Optics for IPD Variation
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Solution Overview
Problem
Conventional head-mounted displays (HMDs) face challenges in accommodating varying interpupillary distances (IPDs) among users, leading to alignment issues and discomfort, as traditional optical designs are not compact or lightweight enough to adjust effectively while maintaining optical performance.
Innovation Solution
A modular HMD system with collimating elements and pupil expanding optics allows for adjustable positioning of eyepieces to suit individual IPDs, using a compact collimating element paired with a larger exit pupil expander, and a control system with mini gyroscopes for real-time recalibration to ensure accurate binocular alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a large eye box is used to accommodate different IPDs, then more IPDs can be accommodated, but the optical system becomes larger and heavier
Solution Approach 1:
The optical system is divided into separate adjustable components (collimating lens, beamsplitter, combiner) that can be independently positioned. This segmentation allows the exit pupil to be moved around in space to create an eyebox that accommodates different IPDs without requiring a large fixed optical system, thereby reducing overall weight.
Solution Approach 2:
The patent implements adjustable IPD mechanisms that allow the optical components to be dynamically repositioned based on the user's IPD. This dynamic adjustment capability enables a compact optical system to accommodate varying IPDs by moving the exit pupil position rather than relying on a large fixed eyebox.
2Adaptability or versatility
If the whole optical system is moved to adjust IPD, then alignment can be achieved, but the mechanics add mass and complexity
Solution Approach 1:
Instead of moving the entire optical system, the patent segments the adjustment mechanism to move only specific components (collimating lens, beamsplitter, combiner) independently. This reduces mechanical complexity and mass while maintaining IPD adjustment capability through selective component repositioning.
Solution Approach 2:
The patent allows movement of optical components along multiple axes (horizontal, vertical, and angular adjustments) to achieve proper alignment. This multi-dimensional adjustment capability enables precise IPD accommodation without requiring complex single-axis mechanisms.
3Stability of the object's composition
If waveguides are fixed in place in a binocular system, then binocular alignment is maintained, but IPD adjustment becomes difficult
Solution Approach 1:
The patent separates the waveguides from the adjustable optical components. The waveguides remain fixed to maintain binocular alignment, while the collimating lens, beamsplitter, and combiner are made adjustable. This segmentation allows IPD adjustment without disrupting the stable binocular alignment provided by the fixed waveguides.
Solution Approach 2:
The adjustable optical components (collimating lens, beamsplitter, combiner) act as intermediaries between the fixed waveguides and the user's eyes. These intermediary elements can be repositioned to accommodate different IPDs while the fixed waveguides maintain the stable binocular optical path.
4Ease of manufacture
If traditional lens trains are used for simplicity, then the optical design is straightforward, but the system is not compact or lightweight
Solution Approach 1:
The patent merges multiple optical functions into a compact folded optical design where the collimating lens, beamsplitter, and combiner work together in an integrated arrangement. This combined approach achieves the required optical performance in a compact, lightweight form factor while maintaining manufacturing feasibility.
Solution Approach 2:
The patent employs a folded optical path that uses multiple reflections to fold the light path into a compact configuration. This dimensional manipulation allows traditional optical functions to be achieved in a space-efficient arrangement that is both compact and manufacturable.
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 solution enables a lightweight, adaptable HMD that can accommodate a wide range of IPDs, reducing eye strain and maintaining optical performance by allowing precise adjustment and recalibration of the optical elements, ensuring a comfortable viewing experience for diverse users.
Implementation Method 1
The collimating element receives the light forming an image. The collimating element collimates the light and outputs the collimated light.
Implementation Method 2
The pupil expanding element receives the collimated light over a first input area and expands the exit pupil so that the light leaves the pupil expanding element over a larger, second output area.
Implementation Method 3
The beamsplitter partially reflects the images onto the concave surface of the spherical combiner.
Implementation Method 4
The spherical combiner reflects a collimated exit pupil through the beamsplitter towards the user's eye.
Data Source
AI summary
Various embodiments of the disclosed subject-matter include a wearable optics device including an adjustment mechanism supportable on a frame adapted to be worn by a user; one or more waveguides in a pre-aligned position relative to the adjustment mechanism; and an optical element moveably attached to the adjustment mechanism to enable the optical element to be moved based on a user preference and to provide an exit pupil for the wearable optics device In various embodiments, the waveguide output is oversized relative to the input region of the optical element. Other devices and apparatuses are also disclosed.