Composite Optical Element for Eye Tracking
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Solution Overview
Problem
Designing compact and stable eye tracking systems for virtual reality and augmented reality applications that can maintain immersion by correlating user gaze with image resolution adjustment is challenging, particularly in head-mounted displays where space and weight are critical.
Innovation Solution
A composite optical element is developed, comprising two optical components bonded with an optical index matching adhesive, functioning as both a lens and a beamsplitter, which transmits visible light and reflects infrared light, allowing for image magnification, correction of optical errors, and integration of an eye tracking unit within a smaller form factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple separate optical components are used for eye tracking in head-mounted displays, then optical functionality is sufficient, but device size and weight increase
Solution Approach 1:
The patent combines multiple optical components (lens and beamsplitter) into a single composite optical element. The first optical component functions as a lens for focusing light, while the second optical component functions as a beamsplitter for separating light paths. These two components are optically coupled to form an integrated element that performs both functions simultaneously, thereby reducing the number of separate components and decreasing overall device weight.
Solution Approach 2:
The composite optical element serves multiple functions within a single integrated structure. It acts as both a lens for image formation and a beamsplitter for directing light to the eye tracking sensor. This multi-functionality eliminates the need for separate optical components, contributing to weight reduction while maintaining complete optical functionality for both display and eye tracking operations.
2Reliability
If multiple separate optical components are used for eye tracking, then optical functionality is sufficient, but device volume increases
Solution Approach 1:
The patent merges the lens and beamsplitter into a single composite optical element with integrated junction surfaces. This consolidation reduces the total volume occupied by optical components in the head-mounted display, as the coupled surfaces eliminate gaps and reduce the overall spatial footprint compared to separate mounted components.
Solution Approach 2:
The composite optical element structure allows one optical component to be optically coupled within or alongside the other component in a nested arrangement. The first optical component and second optical component are positioned such that their junction surfaces are optically coupled, creating a compact nested configuration that minimizes the volume required for the optical system.
3Manufacturing precision
If optical components are coupled with junction surfaces, then manufacturing precision is improved, but alignment difficulty increases
Solution Approach 1:
The patent introduces an optical coupling medium or adhesive layer as an intermediary substance between the first and second optical components. This intermediary material facilitates precise optical coupling by filling gaps and providing a stable bonding interface, thereby achieving high manufacturing precision while simplifying the assembly process compared to direct mechanical alignment without such a medium.
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 composite optical element enhances user experience by enabling a compact, lightweight head-mounted display that maintains high image quality and adjusts resolution based on user gaze, increasing field of view and reducing peripheral image resolution, thus enhancing immersion in VR and AR environments.
Implementation Method 1
The second junction surface is coupled to the first junction surface to form a beam splitter that transmits light in a first band (e.g., visible light) and reflects light in a second band (e.g., infrared light) toward the end surface
Implementation Method 2
The first optical component and the second optical component are optically coupled together
Data Source
AI summary
A composite optical element includes a first optical component and a second optical component. The first optical component includes a first front surface, a first back surface, and a first junction surface. The second optical component that includes an end surface, a second front surface, a second back surface, and a second junction surface. The first front surface and the second front surface together form a first surface of the composite optical element, and the first back surface and the second back surface together form a second surface of the composite optical element. The second junction surface is coupled to the first junction surface to form a beam splitter that transmits light in a first band and reflects light in a second band toward the end surface.