Adjustable Optical Combiner for Mixed Reality Headsets
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Solution Overview
Problem
Optical combiners in mixed reality systems often fail to exhibit desired optical characteristics, making it difficult to simultaneously view computer-generated and real-world images effectively.
Innovation Solution
A head-mounted device with a partially reflective and transparent optical combiner having a curved surface, coupled with actuators that allow mechanical adjustments to the combiner's position and curvature, enabling precise focusing and overlay of virtual images on real-world objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed optical combiner is used, then the device structure is simple, but the optical characteristics cannot be adjusted to achieve desired focusing and overlay effects
Solution Approach 1:
The patent applies the dynamics principle by transforming the fixed optical combiner into an adjustable one. The optical combiner is coupled to the head-mounted support structure via a mechanical adjustment mechanism that allows it to be positioned at different locations and orientations. This enables the optical characteristics (such as focal point, field of view, and overlay alignment) to be dynamically adjusted to match different user requirements and head positions, resolving the contradiction between adaptability and structural simplicity.
2Manufacturing precision
If the optical combiner is made with a curved surface to improve focusing, then the lens power is increased, but the manufacturing complexity and precision requirements increase
Solution Approach 1:
The patent applies the spheroidality principle by incorporating a curved surface on the optical combiner. The curved surface acts as a mirror lens that focuses display image light toward the user's eyes. The curvature provides inherent optical focusing power, improving image sharpness and reducing the need for additional complex lens elements. While curved surfaces do increase manufacturing complexity compared to flat surfaces, the patent balances this by using the curvature in conjunction with adjustable positioning to achieve the desired focusing precision.
3Length of moving object
If the optical combiner is positioned closer to the eye boxes, then the virtual image distance is shortened, but the field of view and real-world light transmission are reduced
Solution Approach 1:
The patent applies the dynamics principle by making the optical combiner position adjustable rather than fixed. The mechanical adjustment mechanism allows the combiner to be positioned at optimal locations that balance virtual image distance and field of view requirements. Users can adjust the combiner position to achieve the desired virtual image distance while maintaining adequate field of view and real-world light transmission, thus resolving the contradiction between these competing parameters.
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
Enables users to view mixed reality content by adjusting the virtual image distance and direction of reflected light, improving the overlay of virtual images on real-world objects with enhanced optical characteristics and user experience.
Implementation Method 1
The optical combiner may be formed from a transparent substrate layer with a coating that is partially reflective and partially transparent. During operation of the head-mounted device, real-world image light from external objects pass through the optical combiner to eye boxes. At the same time, display image light that is produced by the display reflects from the optical combiner towards the eye boxes.
Implementation Method 2
The optical combiner may have a curved surface (a surface with a curved cross-sectional profile) such as a curved surface with compound curvature (Gaussian curvature) that forms a mirror lens (sometimes referred to as a free-form mirror lens). Display image light from the display of the removable portable device reflects from the mirror lens of the optical combiner towards the eye boxes. The lens function of the optical combiner helps focus light from the display for viewing by the user's eyes in the left and right eye boxes.
Data Source
AI summary
An optical system may include a head-mounted support structure configured to receive a removable portable electronic device with a display to form a head-mounted device. A head-mounted device may also be formed by incorporating a non-removable display into a head-mounted support structure. An optical combiner may be coupled to the head-mounted support structure. During operation of the head-mounted device, real-world image light passes through the optical combiner to eye boxes in which the eyes of a user are located. Display image light from the display reflects from a curved partially reflective surface of the optical combiner towards the eye boxes. To make optical adjustments such as virtual image distance adjustments, one or more actuators may be used to mechanically adjust the optical combiner.